Untitled - 13th European Conference on Fungal Genetics

Transcription

Welcome
9th International Symposium on Septoria Diseases of Cereals, Paris, France
Welcome to the 9th International Symposium on Septoria Diseases for 2 and a half days of
scientific discussions in Paris.
This meeting is focused on Septoria diseases of wheat (Zymoseptoria, Parastagonospora,
Pyrenophora) and related diseases of barley and other cereals. Even though a majority of
communications is related to Zymoseptoria-wheat interactions, a significant number of
communications are indeed offered on Parastagonospora, Pyrenophora, Rhynchosporium and
les studies species such as Ramularia, and Rhynchosporium. The Symposium has been
successful in bringing together more than 160 scientists from diverse fields such as plant
pathology, plant breeding, molecular biology, genomics, population genetics and epidemiology
from around the world.
We do hope that this International meeting will foster exchanges between these different
scientific communities. Indeed, these links are required to develop multidisciplinary research
projects that will lead to a better understanding these complex diseases and to the
development of novel, efficient and safe control methods.
PLANNING AT A GLANCE
Thursday, April 7th
08:30 09:00
09:00 09:10
Registration
Introduction
Friday, April 8th
Satellite Meeting 2:
08:40 Epidemiology, cultural
09:20
management and
fungicide resistance
09:20 Keynote Lecture
09:50
09:50 Pathogen Genetics and
10:20
Genomics
10:20 Coffee Break
10:50
10:50 Pathogen Genetics and
12:10
Genomics
12:10 Lunch Break
13:30
09:10 10:00
Keynote Lecture
10:10 10:40
Coffee Break
10:40 12:10
Pathogen evolution and
Population Biology
12:10 13:30
Lunch Break
13:30 15:40
Epidemiology, cultural
management and
13:30 15:20
Pathogen Genetics and
Genomics
15:40 16:10
Coffee Break
15:20 15:50
Coffee Break
16:10 18:10
Epidemiology, cultural
management and
15:50 17:50
Cell Biology and HostPathogen Interactions
18:10 20:00
Poster Session & Wine
and cheese
17:50 18:35
18:35 19:30
19:30 21:00
Saturday, April 9th
08:40 10:20
Cell Biology and HostPathogen Interactions
10:20 10:50
Coffee Break
10:50 12:40
Host Genetics and
Resistance Breeding
12:40 14:00
Lunch Break
14:00 15:50
Host Genetics and
Resistance Breeding
15:50 16:00
16:00 16:30
Conclusion
Departure Coffee
ZT Annotation
Poster Session & Drinks
Gala Buffet ONSITE
SESSIONS Sponsoring
Session 1: Pathogen evolution and Population Biology, is supported by GRDC, AUSTRALIA.
Session 2: Epidemiology, cultural management and fungicide resistance, is supported by SYNGENTA
and DUPONT.
Session 3: Pathogen Genetics and Genomics, is supported by BAYER CROP SCIENCE.
Session 5: Host Genetics and Resistance Breeding, is supported by BSPP, CETAC and KWS.
TABLE OF CONTENTS
ISSDC COMMITTEE .................................................................................................................................. 5
SCIENTIFIC PROGRAM............................................................................................................................. 6
THURSDAY, APRIL 7th 2016 ................................................................................................................ 6
FRIDAY, APRIL 8th 2016 ...................................................................................................................... 7
SATURDAY, APRIL 9th 2016 ................................................................................................................ 9
KEYNOTE LECTURE ................................................................................................................................ 10
ABSTRACTS ............................................................................................................................................ 10
SPEAKER ................................................................................................................................................ 14
ABSTRACTS ............................................................................................................................................ 14
Session 1: Pathogen evolution and population biology .................................................................. 15
Session 2: Epidemiology, cultural management and fungicide resistance ..................................... 31
Session 3: Pathogen genetics and genomics.................................................................................... 32
Session 3: Pathogen genetics and genomics.................................................................................... 33
Session 4: Cell biology and host-pathogen interactions ................................................................. 52
Session 5: Host genetics and resistance breeding ........................................................................... 58
POSTER .................................................................................................................................................. 66
ABSTRACTS ............................................................................................................................................ 66
Session 1: Pathogen evolution and population biology ................................................................. 67
Session 2: Epidemiology, cultural management and fungicide resistance ..................................... 72
Session 3: Pathogen genetics and genomics.................................................................................. 105
Session 5: Host genetics and resistance breeding ......................................................................... 120
AUTHOR INDEX ................................................................................................................................... 140
ACKNOWLEDGEMENTS ....................................................................................................................... 142
LIST OF PARTICIPANTS……………………………………………………………………………………………………........... 146
ISSDC COMMITTEE
Organising committee
Chair, Richard Oliver, Curtin University, Perth, Australia
Chair, Marc-Henri Lebrun, INRA, AgroParisTech, Thiverval-Grignon, France
International Scientific committee
James Brown, JIC, Norwich, UK
Timothy Friesen, USDA, Fargo, USA
Steve Goodwin, Purdue University, West Lafayette, IN, USA
Gert Kema, WUR, Wageningen, The Netherlands
Marc-Henri Lebrun, INRA, AgroParisTech, Thiverval-Grignon, France
Ricardo Madariaga, INIA, Chile
Bruce McDonald, ETH, Zurich, Switzerland
Richard Oliver, Curtin University, Perth, Australia
Pawan Singh, CIMMYT, Mexico
Peter Solomon, CSIRO, Canberra, Australia
Eva Stukenbrock, MPI, Kiel, Germany
Amor Yahyaoui, CIMMYT, Mexico
SCIENTIFIC PROGRAM
THURSDAY, APRIL 7th 2016
8h30 – 9h00
Registration
9h00 – 9h10
Introduction
9h10 – 9h40
Keynote Lecture 1: Cause and effects: bottlenecks in the discovery and deployment
of effectors and markers for the control of cereal Dothideomycete diseases.
Richard OLIVER
Marc-Henri LEBRUN
9h40 – 10h10 Keynote Lecture 2: Genome dynamic and accessory elements in the plant pathogenic
fungus Zymoseptoria tritici - Eva STUKENBROCK
10h10 – 10h40 Coffee Break
10h40 – 12h10 Session 1: Pathogen evolution and population biology
10h40 – 11h10 Plenary 1: How genomic plasticity contributes to virulence evolution in Zymoseptoria
tritici – Daniel CROLL
11h10 – 11h30 Population genetic structure and host specialization in the fungal plant pathogen
Zymoseptoria tritici – Lilian GOUT
11h30 – 11h50 The power of GWA to detect natural genetic variation associated with pathogeny in
Zymoseptoria tritici – Anne GENISSEL
11h50 – 12h10 Independent amplification of a housekeeping gene and its evolutionary significance
in the Dothideomycetes – Braham DHILLON
12h10 – 13h30 Lunch Break
13h30 – 18h10 Session 2: Epidemiology, cultural management and fungicide resistance
13h30 – 14h00 Plenary 2: The epidemiology, disease management and evolution of fungicide
resistance in Zymoseptoria tritici – Bart FRAAIJE
14h00 – 14h20 Recent evolution of Succinate DeHydrogenase Inhibitors (SDHIs) and De-Methylation
Inhibitors (DMI) sensitivity of Zymoseptoria tritici European population – Stefano
TORRIANI
14h20 – 14h40 Spatio-temporal dynamics of fungicide resistance in French populations of
Zymoseptoria tritici – Anne-Sophie WALKER
14h40 – 15h00 Characterising levels of fungicide resistance in the wheat pathogen Zymoseptoria
tritici in Australia – Andrew MILGATE
15h00 – 15h20 The disease severity -yield loss relationship in leaf blotch diseases of wheat
Andrea FICKE
15h20 – 15h40 Prediction of Zymoseptoria tritici based weather risk models - Lise Nistrup
JORGENSEN
16h10 – 16h30 Comparison of varietal mixtures of durum wheat for Septoria leaf blotch
(Zymoseptoria tritici) progression and grain yield – Waad AKROUTI
16h30 – 16h50 Reduction of Septoria leaf blotch propagation in cultivar mixtures: exploring
mechanisms through controlled conditions experimentation and modelling
Tiphaine VIDAL
16h50 – 17h10 Modelling the influence of wheat canopies on Zymoseptoria tritici epidemics
Guillaume GARIN
17h10 – 17h30 Investigation of the mechanisms of sexual reproduction in Zymoseptoria tritici and
their consequences on STB dynamics – Frédéric SUFFERT
17h30 – 17h50 Does Zymoseptoria tritici accelerate leaf apical senescence in winter wheat plants cv.
Soissons grown under contrasted nitrogen conditions? - Marie-Odile BANCAL
17h50 – 18h10 Response of French Zymoseptoria tritici populations to temperature at different
spatio-temporal scales – Anne-Lise BOIXEL
18h10 – 20h00 Poster Session & Wine and Cheese cocktail on site
FRIDAY, APRIL 8th 2016
8h40 – 9h20
Session 2: Epidemiology, cultural management and fungicide resistance
8h40 – 9h00
Leaf blotch on durum wheat in France: characterization of the species complex
responsible of the disease and focus on Parastagonospora nodorum
Romain VALADE
9h00 – 9h30
Keynote Lecture 3: Regulation of chromatin structure and its application to the
understanding of Septoria biology – Michael FREITAG
9h30 – 15h20 Session 3: Pathogen genetics and genomics
9h30 – 10h00 Plenary 3: Identification of necrotrophic effectors in Parastagonospora nodorum
using genome wide association studies – Tim FRIESEN
10h00 – 10h20 Wide spread signatures of selection at secreted peptidases in a fungal plant pathogen
Patrick BRUNNER
10h50 – 11h10 Utilizing gene tree variation to identify candidate effector genes in Zymoseptoria
tritici – Megan McDONALD
11h10 – 11h30 Functional Studies on the Accessory Chromosomes of Zymoseptoria tritici
Michael HABIG
11h30 – 11h50 Accessory chromosome instability during mitosis and the impact of histone
methylation shown by experimental evolution of Zymoseptoria species
Mareike MOLLER
11h50 – 12h20 Plenary 4: Functional genomics approaches for unravelling the Zymoseptoria triticiwheat host-pathogen interaction – Jason RUDD
13h40 – 14h00 The ZtVf1 transcription factor regulates development and virulence in the foliar
wheat pathogen Zymoseptoria tritici – Rahim MEHRABI
14h00 – 14h20 From tools to functional genomics; elucidating the stealth pathogenesis of
Zymoseptoria tritici – Yaadwinder SIDHU
14h20 – 14h40 Identification of novel factors involved in dimorphism and pathogenicity of
Zymoseptoria tritici – Alexander YEMELIN
14h40 – 15h00 Investigating the genetic structure and diversity of the barley pathogen Ramularia
collo-cygni – Michael HESS
15h00 – 15h20 A functionally conserved GAL4-like transcription factor regulates effector expression
and virulence of two major fungal pathogens of wheat – Kar-Chun TAN
15h50 – 17h50 Session 4: Cell bology and host-pathogen interactions
15h50 – 16h20 Plenary 5: Genetic dissection of host susceptibility in wheat-necrotrophic pathogen
interactions – Justin FARIS
16h20 – 16h50 Necrotrophic effectors from Zymoseptoria tritici – Graeme KETTLES
16h50 – 17h10 Identification and functional characterization of putative (a)virulence factors in the
fungal wheat pathogen Zymoseptoria tritici – Amir MIRZADI GOHARI
17h10 – 17h30 Zymoseptoria tritici pathogenicity is determined by isolate-specific virulence factors
Andrea SANCHEZ VALLET
17h30 – 17h50 Transcriptional profiling of four Zymoseptoria tritici isolates differing in virulence.
Javier PALMA-GUERRERO
17h50 – 18h35 Zymoseptoria tritici Annotation workshop
17h50 – 18h05 A detailed manual curation of the Zymoseptoria tritici IPO323 genome coupled with
RNAseq analysis on susceptible and resistant wheat – Robert KING
18h05 – 18h20 Community annotation using WebApollo for PhytoPath species – Pedro HELDER
18h20 – 18h35 Discussions
18h35 – 19h30 Poster Session and drinks
19h30 – 21h00 Gala Buffet ON SITE
SATURDAY, APRIL 9th 2016
08h40 – 10h20 Session 4: Cell biology and host-pathogen interactions
08h40 – 9h00 A novel fungal PAMP identified in Rhynchosporium commune is recognised in dicots
Anna AVROVA
9h00 – 9h20
A role for random, humidity-dependent epiphytic growth in infection of wheat by
Zymoseptoria tritici – Helen FONES
9h20 – 9h40
gamma-aminobutyric acid: A regulator of asexual reproduction and pathogenicity in
the wheat pathogen, Parastagonospora nodorum – Oliver MEAD
9h40 – 10h00 Combination of confocal microscopy and RNAseq reveals dramatic inter- and intraspecies diversity of Zymoseptoria spp. during wheat infection – Janine HAUEISEN
10h00 –
10h20
Chlorophyll fluorescence allows the rapid differentiation of varietal responses to
Zymoseptoria tritici in winter wheat – Rumiana RAY
10h50 – 15h50 Session 5: Host genetics and resistance breeding
10h50 – 11h20 Plenary 6: Host defences against Zymoseptoria tritici – Ari SADANANDOM
11h20 – 11h40 Rapid cloning of genes in wheat using targeted sequence capture
Burkhard STEUERNAGEL
11h40 – 12h00 Frequent and widespread integration of decoy domains derived from protein targets
of pathogen effectors into plant NLR immune receptors – Thomas KROJ
12h00 – 12h20 Cross-Cultivar Transcriptomics: A novel method for comparing pathogen-induced
gene expression between non-model and polyploid host varieties – Adam TARANTO
12h20 – 12h40 Cloning of Stb6 – the first gene conferring race-specific resistance against the
Septoria tritici blotch disease – Cyrille SAINTENAC
14h00 – 14h20 A trade-off between yield and Septoria resistance in wheat – James BROWN
14h20 – 14h40 SNP mapping and wheat genome sequence analysis identified linked QTL and genes
that respond differently to SNB across environments – Michael FRANCKI
14h40 – 15h00 Revised map locations for the Stb2 and Stb3 genes for resistance to Septoria tritici
blotch on chromosome arms 1BS and 7AS of wheat – Stephen GOODWIN
15h00 – 15h20 Genetic architecture of Septoria tritici blotch resistance in French elite winter wheats
Delphine HOURCADE
15h20 – 15h35 QTLs for partial resistance to Zymoseptoria tritici in durum wheat recombinant inbred
line populations – Marco MACCAFERRI
15h35 – 15h50 Novel and broad-spectrum resistance to Zymoseptoria tritici in durum wheat - Lamia
AOUNI
15h50 – 16h00 Conclusion Marc-Henri LEBRUN
16h00 – 16h30 Departure, Coffee
KEYNOTE LECTURE
ABSTRACTS
SPEAKER ABSTRACTS
Key note Lecture 1
Thursday 7 April
09:10 - 09:40
OLIVER Richard P (1)
(1) Centre for Crop and Disease Management, Curtin University, Perth, Australia
Cause and effects; bottlenecks in the discovery and deployment of effectors
and markers for the control of cereal Dothideomycete diseases.
The most economically damaging foliar pathogens of wheat and barley in Australia are the
Pleosporales Parastagonospora nodorum (Septoria nodorum blotch - SNB), Pyrenophora
tritici-repentis (tan spot - TS) and P. teres (barley net blotch NB). The main pathogens of
legumes and oilseeds are the related Leptosphaeria maculans and various Ascochyta species.
Taxonomically nearby is the main pathogen of wheat in Europe, Zymoseptoria tritici. At the
time of the Tunisia meeting of this group, all the cereal pathogens were, from a practical point
of view, in the same state. No strong resistance was available and genetic analysis of resistance
revealed multiple weak QTL that varied between season, localities and isolates. Few markers
were in use. The discovery of a PtrToxA zenologue in P. nodorum ushered in a period of rapid
improvement. A new dogma was established whereby these pathogens exerted pathogenicity
by producing a number of effectors (Necrotrophic effectors) that induced a defence-like
reaction in host germplasm carrying paradoxical sensitivity genes. The NEs were all small,
secreted, cysteine-rich proteins. All that we needed to do was find all the effectors, and breed
host germplasm that lacked all the sensitivity genes. The dogma has had some notable
successes. Breeding for TS and SNB in Australia has been substantially accelerated via the
deployment of (for SNB) three effectors that, in retrospect, only partially fulfil the dogmatic
criteria. SNB has turned out to be interestingly complex in its behaviour. Deployment of the
effectors outside Australia has been much less successful. I will examine reasons for this
observation. The dogma has focussed research in other species. The search for small secreted,
cys-rich proteins has been extensive but so far frustrating. Issues with genome assemblies,
gene calling and effector properties have all been significant. More fundamentally, it has
become apparent that the secretion into culture filtrates of stable proteins with NE activity
may turn out to be exceptional rather than common. Strategies for the control of these
intractable diseases needs to be driven by multifaceted studies that acknowledge the diverse
properties of these pathogens and their effector repertoires.
SPEAKER ABSTRACTS
Keynote Lecture 2
Thursday 7 April
9:40 – 10:10
STUKENBROCK Eva H. (1),
MOELLER Mareike (1), SCHOTANUS Klaas (1), L. SOYER Jessica (2), FREITAG
Michael (3)
(1) Christian-Albrechts University of Kiel, Environmental Genomics, Kiel, Germany and Max Planck
Institute for Evolutionary Biology, Plön, Germany (2) INRA, BIOGER, INRA, AgroParisTech, ThivervalGrignon, France (3) Department of Biochemistry and Biophysics, Oregon State University, Corvallis,
Oregon, USA
Genome dynamic and accessory elements in the plant pathogenic fungus
Zymoseptoria tritici
Accessory chromosomes are present in the genomes of many organisms. In fungi these chromosomes
are present at different frequencies in populations and usually characterized by higher repetitive DNA
content and lower gene density. In the fungal pathogen Zymoseptoria tritici, as many as eight discrete
accessory chromosomes occur in different strains comprising up to 12% of the total genome. So far no
functional role has been assigned to these chromosomes. Comparative genome analyses show that
genes on accessory chromosomes accumulate considerably more mutations compared to genes on
core chromosomes consistent with a relaxation of selective constraints. Yet, accessory chromosomes
have existed as separate entities in the karyotypes of Zymoseptoria species over longer evolutionary
time. We have set out to investigate the properties of accessory chromosomes underlying their rapid
evolution and sequence dynamics. We used ChIP-seq with antibodies against the centromere specific
histone CenH3, as well as the euchromatic mark H3K4me2 and the heterochromatic marks H3K9me3
and H3K27me3 to identify centromeres and determine the distribution and proportion of euchromatin
and heterochromatin in the Z. tritici genome. Next, we conducted a detailed computational analysis of
subtelomeric repeats to compare telomeres of core and accessory chromosomes. We show that
accessory chromosomes have centromeres and telomeres identical to those of core chromosomes.
However, accessory chromosomes of Z. tritici have dramatically higher enrichment of
heterochromatin, consistent with a higher proportion of repetitive DNA and an overall silencing of
transcription. The overall heterochromatic state of accessory chromosomes may also contribute to
their instability. We find that rearrangements and loss of accessory chromosomes not only occur, as
previously described during meiosis, but also to a high extent during mitosis. Together our results
suggest a central role of chromatin modifications in the maintenance of chromosome stability in Z.
tritici. Dynamic changes of chromatin structures can thereby contribute to karyotypic variation and
chromosome evolution in this important pathogen.
SPEAKER ABSTRACTS
Key note lecture 3
Friday 8 April
09:00 - 09:30
FREITAG Michael (1)
SCHOTANUS Klaas (2), MÖLLER Mareike (2), CONNOLLY Lanelle R. (1), SMITH
Kristina M. (1), STUKENBROCK Eva H. (2)
(1) Dept. of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
Environmental Genomics, CAU Kiel and MPI for Evolutionary Biology, Plön, Germany
(2)
Regulation of chromatin structure and its application to the understanding of
Septoria biology
Fungi are excellent models for comparative studies of chromatin biology. We will present
selected examples to illustrate this point, focusing on patterns of heterochromatin
distribution and regulation in various fungi, including Zymoseptoria tritici. In previous work,
we found that centromeric chromatin of Neurospora and Fusarium species is heterochromatic
and transcriptionally silent. This is not the case in several Zymoseptoria species. The three
genera also show differences in the distribution and regulation of two commonly studied
histone marks associated with gene silencing, histone H3 lysine 9 and lysine 27 trimethylation
(H3K9me3 and H3K27me3). In Neurospora, ~5% of the genome is associated with H3K27 diand trimethylation, while this percentage is higher in the other two genera, reaching ~33% of
the entire genome in some Fusarium species. Deleting genes responsible for H3K27
methylation controls the expression of more than 25% of all genes in several Fusarium species,
but less in Zymoseptoria and Neurospora. Interactions between H3K9 and H3K27 methylation
are being uncovered and the interplay between different histone marks appears to be
different in different species. Removal of H3K27me3 yields new opportunities to express the
"cryptic genome", regions that are usually transcriptionally silent when fungi are grown under
lab conditions and not under environmentally conducive conditions (e.g. in planta or in
competition with other microbes). Our work has implications on the study of secondary
metabolite gene clusters and pathogenicity factors of many fungi that infect animals and
plants, including species of the Septoria group.
SPEAKER
ABSTRACTS
SPEAKER ABSTRACTS
Session 1: Pathogen evolution and population biology
Plenary lecture
Thursday 7 April
10:40 - 11:10
CROLL Daniel (1)
HARTMANN Fanny (1), SÁNCHEZ-VALLET Andrea (1), ZALA Marcello (1)
(1) Plant Pathology, ETH Zurich, Zurich, Switzerland
How genomic plasticity contributes to virulence evolution in Zymoseptoria
tritici
Zymoseptoria tritici causes Septoria tritici blotch (STB) on wheat. Disease control is challenging
because host resistance can break down quickly and the pathogen rapidly evolved resistance
to all major fungicide classes. The extraordinary adaptive potential of the pathogen is likely
driven by large population sizes and frequent sexual reproduction. But how genetic variation
is generated in the genome and how this variation contributes to virulence evolution is poorly
understood. Accessory chromosomes (i.e. chromosomes not shared by all members of the
species) differ significantly in length among homologs and undergo deleterious
rearrangements during meiosis. We aimed to understand whether core chromosomes do also
show evidence of genomic plasticity. To this end, we generated a complete genome assembly
using long-read technology and high-density genetic maps of an isolate from a Swiss wheat
field. Comparative genomics analyses showed that core chromosomes of the newly assembled
genome harboured orphan regions not found in the reference genome. Orphan regions were
most likely generated by non-homologous recombination among copies of transposable
elements. Genes in orphan regions were more likely to show evidence for degeneration,
however a subset of orphan genes had sequence signatures and transcriptional profiles
indicative of a role in virulence. Orphan genes not found in the reference genome will be an
important complement to the currently investigated set of candidate virulence genes. To
understand the role genetic variation plays in virulence at the population level, we performed
a genome-wide association study of 106 Illumina sequenced isolates. Characterization of the
associated chromosomal regions showed that differences in virulence were most likely caused
by non-synonymous substitutions in genes encoding cell wall-degrading enzymes and deletion
polymorphisms affecting a candidate avirulence gene. In conclusion, chromosomal plasticity
and frequent recombination generated highly diverse pathogen populations capable of rapidly
gaining or losing virulence loci in response to selection pressure imposed by the host.
SPEAKER ABSTRACTS
Thursday 7 April
11:10 - 11:30
GOUT Lilian (1)
CONFAIS Johann (2), MASSOT Marie (3), DUCASSE Aurélie (2), VALADE Romain
(3)
(1) BIOGER, INRA, AgroParisTech, Thiverval-Grignon, France (2) BIOGER, AgroParisTech, INRA,
Thiverval-Grignon, France, (3) ARVALIS, Pathologie Végétale, Thiverval-Grignon, France
Population genetic structure and host specialization in the fungal plant
pathogen Zymoseptoria tritici
Zymoseptoria tritici causes septoria tritici blotch of wheat, one of the most important diseases
of this crop worldwide. Yield losses can reach 50% in disease-conducive climates and
epidemics occur regularly both on hexaploid bread wheat (Triticum aestivum) and tetraploid
durum wheat (Triticum turgidum ssp. durum). Isolates of Z. tritici exhibit both cultivar
specificity (ability to infect only some cultivars of either bread or durum wheat) and host
species specificity (ability to only infect one or the other wheat species). In France, the major
bread wheat growing areas are located in the Northern regions, whereas durum wheat is
mainly cultivated in the South-East region. Besides these traditional growing regions, both
species are also cultivated in the Centre and South-West regions of France. In this study, we
exploited these contrasted agrosystems to investigate, at a population level, the extent of host
specialization in Z. tritici and to test whether this specificity towards bread or durum wheat
had a significant effect on the genetic structure of the fungal populations. A set of 700 Z. tritici
isolates were sampled from naturally infected fields of bread and durum wheat in these four
regions, and genotyped using 12 microsatellite markers. The level of host specialization of 72
isolates from these populations was also determined by cross inoculation experiments on a
panel of bread and durum wheat cultivars.
SPEAKER ABSTRACTS
Thursday 7 April
11:30 - 11:50
GENISSEL Anne (1)
GUILLOT Marie-Pierre (2), CONFAIS Johann (1), GOUT Lilian (2), LEBRUN MarcHenri (1)
(1) BIOGER, INRA, AgroParisTech, Thiverval-Grignon, France
Thiverval-Grignon, France
(2) BIOGER, AgroParisTech, INRA,
The power of GWAS to detect natural genetic variation associated with
pathogeny in Zymoseptoria tritici
Association genetics is a powerful approach to search for the genetic basis of complex traits,
including plant diseases caused by pathogens. The goal of our study is to shed light on new
genetic components that are associated with natural phenotypic variation in population
samples of Zymoseptoria tritici. The traits we are mostly interested in are the disease
symptoms caused by Zt on wheat leaves in laboratory conditions. We used a panel of french
strains to perform a Genome Wide Association Study. Second generation sequencing data
were obtained using Illumina technology, in order to extract SNPs and short indels. Our
phenotypic measurements corresponded to: (1) the percent of leaf area covered with pycnidia
and the total number of pycnidia at 21 days post-inoculation; (2) the ability of the strains to
grow and penetrate the leaf surface between 4 and 5 days post-inoculation, which was
obtained using fluorescent microscopy. We used ANOVA models to estimate the adjusted
means of our quantitative traits. For the macroscopic traits (leaf area with pycnidia and
number of pycnidia), we also compared models which included or not the ability of the strains
to develop at the leaf surface post-inoculation, in order to disentangle the host-pathogen
interaction between the inner and outer compartments of the plant. GWAS was performed
using genome-wide efficient mixed model association. Such a model accounts for the
relatedness among individuals. Significant statistical results targeting candidate genes will be
presented.
SPEAKER ABSTRACTS
Thursday 7 April
11:50 - 12:10
DHILLON Braham (1)
KEMA Gert H J (2), BLUHM Burton H (1), GOODWIN Stephen B (3)
(1) University of Arkansas, Fayetteville, USA (2) Wageningen University, Wageningen, The Netherlands
(3) USDA, ARS Purdue University, West Lafayette, USA
Independent amplification of a housekeeping gene and its evolutionary
significance in the Dothideomycetes
Genomes are in a state of flux, always evolving and morphing. What we observe in a
sequenced genome is a snapshot in time. Comparative genomics allows us to piece together
a scenario of events that could explain the past and current state of a genome. Traditionally,
genomes are split into two compartments, coding and non-coding, and most effort has been
to characterize the coding / genic part. However, evidence supporting a role for the noncoding part, especially transposable elements (TEs), has accumulated during the past few
decades. TEs have now been established as key players in both the functional and structural
evolution of genomes. Analysis of the genome of the banana pathogen, Pseudocercospora
fijiensis (Pfi), identified a capture and amplification of a housekeeping gene, Histone H3, by
TEs from the hAT family of DNA transposons. A search of other Dothideomycete genomes
revealed a parallel event in two corn pathogens, Cercospora zeae-maydis (Czm; sequenced by
the JGI) and C. zeina (Cze; sequenced in-house). Interestingly, two additional in-house
Cercospora genomes of the soybean pathogens C. sojina and C. kikuchii lacked this event,
which can be attributed to less TE amplification in the soybean pathogens compared to the
corn pathogens. Outside of the Capnodiales, we observed degenerate histone H3 copies in
the Leptosphaeria maculans (Lma) and Parastagonospora nodorum (Pno) genomes. These
species are closely related to Pyrenophora tritici-repentis (Ptr) where a similar event was
described previously. However, there were differences in the rate of histone H3 amplification
between the two orders. In the Pleosporales, the H3 gene is present in low copy numbers of
26, 10, and 9 in Ptr, Lma and Pno, as opposed to the Capnodiales with 787, 240, and 640
histone copies in the Pfi, Czm and Cze genomes, respectively. At the nucleotide level, the Ptr
H3 copies vary considerably compared to those in the Pfi, Czm and Cze genomes, suggesting
an independent origin for the hAT mediated H3 amplification in each order. Mechanisms such
as RIP exist in fungi to minimize TE expansion. Amplification of the Histone H3 gene by hAT
TEs should make it susceptible to the RIP process. However, in Pfi all 787 copies of the H3 gene
except for the original were inactivated by RIP, which may indicate that the original histone
H3 gene was under strong negative selection pressure until the amplified H3 copies diverged
by accumulation of RIP-introduced mutations.
SPEAKER ABSTRACTS
Plenary lecture
Thursday 7 April
13:30 - 14:00
FRAAIJE Bart (1)
(1) Rothamsted Research, Biological Chemistry and Crop Protection Department, Harpenden,
Hertfordshire, UK
The epidemiology, disease management and evolution of fungicide resistance
in Zymoseptoria tritici
Septoria leaf blotch caused by the fungal pathogen Zymoseptoria tritici is globally one of the
most important diseases on wheat crops. Since 1981, Septoria leaf blotch has remained the
most economically important foliar disease of UK wheat crops. Crops get infected by airborne
sexually produced ascospores and after high rainfall during spring and early summer high
levels of disease can reach the upper canopy of the crop through rain splash mediated
dispersal of asexually produced spores. The infected wheat leaves turn brown and die
prematurely and due to loss of photosynthesis during grain filling this will impact on yield.
Yields losses up to 6 tonnes per hectare have been recorded for susceptible varieties under
high diseases pressure; with an average annual yield loss of 20%. Annual economic losses in
the UK due to Septoria leaf blotch are considered to be in excess of £200 million, even after
the use of full fungicide programme on most wheat crops. Due to lack of host resistance,
control of Septoria has so far been heavily dependent on chemical control. Unfortunately,
Zymoseptoria tritici has been able to shown a remarkable adaptation to fungicides over the
years and the current UK population is resistant to different groups of systemic fungicides,
including Methyl Benzimidazole Carbamate (MBC), Quinone Outside Inhibitor (QoI) and azole
fungicides. As a consequence, farmers and farm advisors have only a few options available to
control the disease on the 1.9 million hectares of wheat currently grown in the UK. Further
threats for future STB control are the first reports of resistant field isolates to the most
effective group of fungicides, the Succinate Dehydrogenase Inhibitors (SDHIs), and loss of
current actives and drying up of the fungicide pipeline due to tighter legislation.
SPEAKER ABSTRACTS
Thursday 7 April
14:00 - 14:20
TORRIANI Stefano (1)
FREY Regula (1), STUERM Carolina (1), WULLSCHLEGER Juerg (1), BIERI Stephane
(1), SCALLIET Gabriel (1), SIEROTZKI Helge (1)
(1) Syngenta, Crop protection AG, Stein, Switzerland
Recent evolution of Succinate DeHydrogenase Inhibitors (SDHIs) and DeMethylation Inhibitors (DMI) sensitivity of European Z. tritici populations
Disease control is critical to cereal production in Europe. European Zymoseptoria tritici
populations are subjected to selection imposed by the use of fungicides. Z. tritici is controlled
by succinate-dehydrogenase inhibitors (SDHIs), demethylation inhibitors (DMIs), quinone
outside inhibitors (QoIs) and multi-site fungicides, such as chlorothalonil. Fungicide resistance
to the major single-site fungicide classes has been reported. Recurring mutations
independently introduced the G143A resistance allele into different genetic and geographic
backgrounds. Sensitivity studies over the past 25 years show that Z. tritici adapted to DMI
through distinct sensitivity shifts since the 1990s. From 2014 a further shift was monitored.
Selection imposed by different DMIs shaped local European populations of Z. tritici
phenotypically and genotypically. From 2012 single isolates with a low level of SDHI adaptation
were reported in Europe, based on different mutations in the target genes (e.g. sdhB-N225T
and sdhC-T79N). In 2015, a new mutation (sdhC-H152R) associated with a moderate
resistance factor was reported from a few fields in Ireland. The impact and the possible
evolution of resistance/adaptation in different genetic backgrounds at target sites and
putative associated fitness costs will be discussed in relation to fungicide resistance
management.
SPEAKER ABSTRACTS
Thursday 7 April
14:20 - 14:40
WALKER Anne-Sophie (1)
BERTRAND Oudot (1), FLORENCE Carpentier (2)
(1) BIOGER, INRA, AgroParisTech, Thiverval-Grignon, France (2) BIOGER, AgroParisTech, INRA,
Spatio-temporal dynamics of fungicide resistance in French populations of
Septoria leaf blotch caused by Zymoseptoria tritici, is one of the most damaging diseases of
wheat. The use of fungicides, aiming to control this disease, is however impeded by the
selection of resistant strains. Therefore, optimizing anti-resistance strategies is one of the keys
of fungicides sustainability and needs a detailed knowledge of population dynamics over time
and space. This was studied while statistically analyzing the 10-year database produced by the
«Performance network», a trial network managed by the French cereals technical institute
Arvalis-Institut du Végétal. Our work aims to (i) identify the spatial and temporal scales
structuring fungicide resistance, and (ii) to evaluate the influence of regional fungicides
strategies on this structure. Six Z. tritici resistant phenotypes were studied. Their frequencies
were collected over France between 2004 and 2014, in 60-70 trials yearly. The spatial
structure was determined using a spatial classification tool (SpoDT) and the temporal
evolution was tested using a linear mixed model. The influence of fungicide strategies was
measured by a conventional linear model. Our results showed a regional delimitation for some
phenotypes. Contrasted expansion rates were calculated, according to modes of action. These
structures were linked to the regional use of some molecules. Nevertheless, other
determinants (e.g. soil and climate variables) should also be considered.
SPEAKER ABSTRACTS
Thursday 7 April
14:40 - 15:00
MILGATE Andrew (1)
ADORADA Dante (1), SPACKMAN Merrin (1), ORCHARD Beverley (1), RENKIN
Melanie (1)
(1) NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga,
Australia
Characterising levels of fungicide resistance in the wheat pathogen
Zymoseptoria tritici in Australia
Zymoseptoria tritici is an important pathogen of wheat globally and is capable of causing 50%
yield loss in susceptible varieties. Control of the disease relies on the use of host resistance,
cultural practices and fungicides. However the pathogen is capable of rapidly overcoming host
resistance in cultivars and modern farming systems favour stubble retention creating ideal
conditions for its survival. Thus, in many countries there has been an over reliance on
fungicides to control the disease. This has led to the evolution of resistance to several classes
of fungicides including the demethylation inhibitors (DMI) and quinine outside inhibitor (QOI).
In Australia Z. tritici is a production constraint in the high rainfall zones of south eastern
Australia. The use of DMI fungicides, in Australia, to control foliar diseases in wheat production
has increased rapidly over the past decade. We have examined a historical set of isolates
spanning from 1979 to 2013 and can confirm the evolution of mutations in the Cyp51 gene
known to reduce DMI sensitivity occurring in Australia for the first time. Isolates carrying the
L50S, Y137F and L50S-Y461S have been phenotyped and their resistance factors estimated to
a number of DMI fungicides. The impact of the emergence of these mutations will be
presented and discussed.
SPEAKER ABSTRACTS
Thursday 7 April
15:00 - 15:20
FICKE Andrea (1)
(1) Norwegian Institute of Bioeconomy, Aas, Norway
The disease severity-yield loss relationship in leaf blotch diseases of wheat
Parastagonospora nodorum together with Zymoseptoria tritici are two of the most yield
reducing diseases in wheat. We, as plant pathologists never fail to cite some dramatic
numbers for yield losses due to our favourite disease to emphasize the significance of our
research. But how relevant is this information for making decisions on applying fungicides or
using resistant varieties on the farm level? Most of the studies used to deduce yield losses
from a certain disease are based on field trials with treated and untreated plots, preferably
with high disease pressure to evaluate the performance of a certain plant protection product.
However, single field trials where fungicide applications and reductions in disease severity are
correlated with yield components are a poor guide to understand how much disease can be
tolerated without economic loss for a grower. This information would be important to give
sound economic advice on integrated pest management, where we should employ thresholds
to minimize external inputs and economic losses. Simple disease severity-yield loss
relationships for leaf blotch diseases have been established based on field studies with a few
wheat cultivars, but can hardly be a guideline for the complexity of yield loss on the farm level.
Different wheat cultivars might compensate differently for early and late disease
development, abiotic factors limit yield potential and influence the yield reducing effect of
diseases greatly. We also usually neglect to account for the other pests, weeds and pathogens
that occupy the same field as the disease we are focusing on, making deductions on yield loss
due to a particular disease less reliable. Based on several years of field trial data on leaf blotch
diseases from diverse locations and under varying climatic conditions in Norway, we are
exploring different modelling approaches to better estimate yield losses due to different
diseases or disease complexes. These yield loss models should be simple, based on a limited
number of factors, robust and accurate enough to ensure farmers will accept and employ
them in their decision making tool box.
SPEAKER ABSTRACTS
Thursday 7 April
15:20 - 15:40
JØRGENSEN Lise Nistrup (1)
ØRUM Jens Erik (2), NIELSEN Ghita Cordsen (3), BLIGAARD Jens (3), HANSEN Jens
Grønbech (4), BABY Sanmohan (4)
(1) Aarhus University, Flakkebjerg, Dept. of Agroecology, Slagelse, Denmark (2) Copenhagen
University, Dept. of Food and resource economy, Copenhagen, Denmark (3) Seges, Skejby, Aarhus,
Denmark (4) Aarhus University, Foulum, Dept. of Agroecology, Tjele, Denmark
Prediction of Zymoseptoria tritici based weather risk models
Risk models based on weather data, information about disease development and thresholds
for decision making on time and type of fungicide applications is traditionally used as
important IPM elements in a sustainable cropping situation. The need for control of
Zymoseptoria tritici varies significantly between years and sites as the severity of septoria
tritici blotch (STB) is well known to be favoured by humid events. Typically, number of days
with precipitation during the spring and summer season has been used in risk models. The DSS
Crop Protection Online (CPO) has in most years given competitive treatments to standard
sprays and generally used less fungicide. In some seasons the model has been somewhat
conservative and due to its simplicity; counting days with precipitation >1 mm and
recommending treatments following 4 days >1mm; too simple to capture all aspects of the
septoria populations dynamics. Hence, a new project was initiated to develop better
predictions for STB disease development using weather data from weather stations operated
by the Danish National Meteorological Office. It has particularly been a wish to include relative
humidity (Rh) and leaf wetness parameters in the new models as well as achieving a better
understanding of correlations between macro and microclimatic parameters. From previous
studies we have found a good relationship between leaf wetness measured at 1 m height
above grass lawns and leaf wetness on exposed leaves in a potato canopy. We expect the
same relationship for a wheat crop. In order to use Rh from standard weather stations to
estimate leaf wetness in a crop canopy, we analysed data on Rh (2m) and leaf wetness
measured at 2 m and 1 m across two years and three locations. Using a threshold of 85 % Rh
measured at 2 m proved to be a good estimate for leaf wetness at 1 m giving only 10% miss
rate. Finally, a «humid hour» was defined as an hour where Rh>85% and/or leaf wetness > 30
minute per hour and/or rain >0.2 mm. Treatment should then be recommended if a period
with more than a certain number (e.g. thresholds of 20, 24 or 36 hours) of consecutive «humid
hours» has occurred. Based on historical weather data from 6 years and 10 trial sites in
combination with disease and yield observations, several empirical models were derived and
compared with the existing CPO model. This exercise clarified the impact from using different
thresholds on treatments numbers across seasons and localities. A specific model using 20
«humid hours» were tested in field trials during two growing seasons and compared with CPO
and standard treatments. This presentation will discuss the results of the modeling exercise
as well as validation of the new models in field trials.
SPEAKER ABSTRACTS
Thursday 7 April
16:10 - 16:30
AKROUTI Waad (1)
ANGAR Houcine (2), BOUKEF Sameh (3), REZGUI Salah (1), BELHADJ SALAH Halim
(1)
(1) National Agronomic Institute of Tunis, Mahragene, Tunisia (2) National Institute of Arable Crops ,
Bousalem, Tunisia (3) Higher Institute of Agriculture , Shott Mariem, Tunisia
Comparison of varietal mixtures of durum wheat (Triticum durum L.) for
Septoria leaf blotch (Zymoseptoria tritici) progression and grain yield
Using varietal mixture with different resistance levels is increasingly used to control Septoria
leaf blotch. To establish good cultivar mixtures it is important to understand the influence of
varietal and environmental parameters on confounding effects between environments and
cultivar mixtures. This study is aiming to investigate the effects of increased tolerance to
septoria using susceptible and tolerant durum wheat mixed cultivars with different
proportions. Pure wheat cultivars (Nassr, Salim) as tolerant , and (Maali and Khiar) as
susceptible, generated five mixtures ([M1 : 75% resistant cultivar (R) and 25% susceptible
cultivar (S)] ; [M2 : 2/3 R and 1/3 S] ; [M3 : 50% R and 50% S] ; [M4 :1/3 R and 2/3 S] ; [M5
:25% R and 75% S]) for each binary association (Nassr and Khiar; Salim and Maali). All
treatments were grown in fields naturally infested with Zymoseptoria tritici and were assessed
for disease progression and grain yield in two divergent growing conditions (Bousalem and
Beja). Cultivars mixtures performed better than susceptible pure line components (Maali and
Khiar) for disease severity, incidence and height of attack. The average of incidence ranged
from 1% for M3 to 37.25% for Khiar at Bousalem and from 3% from M1 to 24.5% for Khiar at
Beja at the vegetative stage. A slight superiority from 5% to 8% was observed with mixtures
M4 and M3 respectively comparing to the pure components Nassr at Bousalem. The best
mixture with a lower level of disease attack was M3 with equal proportions. This mixture could
be sought to alleviate Zymoseptoria attack and may maintain an acceptable grain yield in both
environments.
SPEAKER ABSTRACTS
Thursday 7 April
16:30 - 16:50
VIDAL Tiphaine (1)
LUSLEY Pauline (1), LECONTE Marc (2), DE VALLAVIEILLE-POPE Claude (2), HUBER
Laurent (1), SAINT-JEAN Sébastien (1)
(1) ECOSYS, AgroParisTech, INRA, Thiverval-Grignon, France (2) BIOGER, INRA, AgroParisTech,
Reduction of Septoria leaf blotch propagation in cultivar mixtures: exploring
mechanisms through controlled conditions experimentation and modelling
Cultivar mixtures can contribute to a sustainable management of foliar diseases such as
septoria leaf blotch. Mixing cultivars differing by their resistance genes makes it possible to
partially protect a susceptible cultivar by a resistant cultivar. Architectural properties of the
mixture cultivar components can have an impact on their capacity to intercept spores and
therefore on disease reduction mechanisms within mixture such as reduction of susceptible
host density and barrier of resistant cultivar on spore dispersion. Efficient mixture design is
often difficult, given the high number of possible combinations and the complexity of
mechanisms involved. Modelling can therefore be a powerful tool to better understand
disease reduction mechanisms and identify characteristics of mixtures of interest. However,
few models take into account both architecture and resistance heterogeneity of canopies. A
modelling approach based on experimental data was used to investigate dispersal
mechanisms in mixed canopies with components differing by both their varietal resistance
and architecture. A controlled experiment was performed with three types of canopies of
1m2: a mixture of two cultivars and pure stands of these cultivars. A linear inoculum source
consisting of an aqueous suspension of spores was disposed in the middle of each canopy and
then placed under a rain simulator generator to generate reproducible spore flux. Horizontal
and vertical spore fluxes were measured at different points in the canopy using traps
composed of microscope slides. Varietal resistance was assessed in parallel. After incubation,
disease severity was measured at leaf level on plants sampled from each canopy. Architecture
characterization allowed reconstruction of realistic 3D mockups of experimental canopies. A
bio-physical model was used to compute splash droplets interception by leaves in 3D
canopies. For each leaf of the virtual canopy, lesion area was deduced from the amount of
intercepted inoculum and from individual leaf resistance level. Simulated spore fluxes and
disease gradients were consistent with experimental measurements. In particular, high leaf
area density resulted in higher spore interception by the canopy and higher disease severity.
In mixed canopies, resistant plants had higher densities and therefore provided an efficient
barrier effect. This modelling approach, now validated on detailed experimental data, can be
used to reconstruct dispersal events observed in the field and understand dispersal
mechanisms involved in complex canopies such as cultivar mixtures.
SPEAKER ABSTRACTS
Thursday 7 April
16:50 - 17:10
GARIN Guillaume (1)
FOURNIER Christian (2), ANDRIEU Bruno (3), ABICHOU Mariem (3), HOULÈS
Vianney (1), PRADAL Christophe (2), ROBERT Corinne (3)
(1) iITK, Montpellier, France (2) AGAP, CIRAD, INRIA, Virtual Plants, Montpellier, France (3) ECOSYS ,
INRA, AgroParisTech, Thiverval-Grignon, France
Modelling the influence of wheat canopies on Zymoseptoria tritici epidemics
Designing sustainable crop protection strategies requires identifying the most influential
factors that drive epidemics. Modeling pathosystems is useful in this exploratory perspective.
This work presents, evaluates and uses a model of Zymoseptoria tritici combined with a virtual
wheat model in 3D. It examines the key factors in the race between plant growth and progress
of the disease to the upper leaves of the canopy. Detailed measurements of wheat
architecture and disease development on the upper leaves were conducted on 3 seasons on
4 wheat lines. The assessments on plants were used to set the parameters of the wheat model.
The epidemic model simulated the data quite well, indicating a consistent response to climate
and canopy architecture. Then, the influence of wheat canopy traits on simulated epidemics
was tested by changing parameters of the wheat model one at a time, under varied climatic
scenarios. This analysis confirms the influence of plant properties on septoria epidemics, such
as the stem growth rate and dimension. It also underlines the complexity of plant-pathogen
interactions that vary with climatic conditions and leaf rank. This work also points out the
strong impact of leaf phenology and leaf senescence on the progress of epidemics. It suggests
that epidemics of septoria are strongly influenced by the green life span of leaves, implying a
local race for fungal growth and reproduction at the scale of each leaf before it becomes
senescent.
SPEAKER ABSTRACTS
Thursday 7 April
17:10 - 17:30
SUFFERT Frédéric (1)
MORAIS Davis (1), DELESTRE Ghislain (1), GELISSE Sandrine (1), LAVAL Valérie (1),
SACHE Ivan (1)
Investigation of the mechanisms of sexual reproduction in Zymoseptoria
tritici and their consequences on STB dynamics
Zymoseptoria tritici is a relevant model to investigate the mechanisms of sexual reproduction
in a pathogenic fungus and its consequences on disease epidemics. Ascospores produced on
wheat debris are the main form of primary inoculum (Suffert et al., 2011) but are also largely
involved at the end of growing season (Duvivier, 2015). We investigated: (1) the contribution
of the ascospores to the early epidemic stages, from the build-up to the release of the primary
inoculum; (2) the epidemiological determinants of the sexual reproduction, at leaf and canopy
scales; (3) a possible trade-off between pathogenicity (asexual stage) and transmission (sexual
stage). In a 8-year field experiment we established that the local presence of contaminated
debris has a strong effect, although transient and dependant on their fungal load (year effect),
on the early dynamic of Septoria tritici blotch (Suffert & Sache, 2011). The amount of primary
inoculum was characterized, coupling spore trapping with qPCR (Morais et al., 2015a); the
pathogenicity of ascospores and pycnidiospores was compared (Morais et al., 2015b); finally,
the origin of primary inoculum was inferred from the comparison of the aggressiveness
profiles of local and distant pathogen populations (Morais et al., 2016). Using an experimental
crossing method (Suffert et al., in prep.), we investigated the effect of a short delay in the coinfection timing of parental isolates (beneficial to ascosporogenesis) and the effect of
variations in lesion density (corroborating field observations). Field results also suggested that
the site of sexual reproduction (leaves and stems) shift in autumn from basal to upper part of
the entire, senescent plants of the previous year, correlatively to their co-infection timing. We
have not established experimentally any adaptive compromise between the two reproduction
modes of Z. tritici (pathogenicity and transmission). We postulate, however, and discuss the
occurrence of trade-offs based on Allee effect at the plant scale. At the end of field epidemics
a low pathogen density on upper leaves would decrease the likelihood of mating between
compatible strains, thus limiting sexual reproduction and transmissibility of the fittest strains,
whose selection is driven by seasonal thermal fluctuations (Suffert et al., 2015).
SPEAKER ABSTRACTS
Thursday 7 April
17:30 - 17:50
BANCAL Marie-Odile (1)
BANCAL Pierre (1), BENSLIMANE Rym (2),
(1) ECOSYS, AgroParisTech, INRA, Thiverval-Grignon, France (2) Institut Supérieur Agronomique de
Chott Mériem, ISA, CM, Chott Mériem, Sousse, Tunisia
Does Zymoseptoria tritici accelerate leaf apical senescence in winter wheat
(cv. Soissons) grown under contrasted nitrogen conditions?
Both disease and nitrogen availability impact green leaf area (GLA), and thus affect yield. Yet
these two factors likely interact together. In this study, interactions between Zymoseptoria
tritici symptoms and leaf apical senescence were studied in glasshouse plants encompassing
large inoculated areas with two contrasted nitrogen regimes to better extrapolate the results
to natural epidemics. From 1/2 to 2/3 of the flag leaf area of the susceptible winter wheat cv.
Soissons was inoculated using a virulent Z. tritici isolate at inoculum concentrations close to
natural conditions. A range of apical senescence rates was obtained by applying two
contrasting conditions of N nutrition from inoculation. Non-destructive assessments were
repeated to characterize the senescence kinetics of both the inoculated zone and leaf apex on
the same leaves from inoculation to full senescence. For each flag leaf, green, necrotic and
apical senescence areas were fitted to appropriate equations. Pycnidia-like structures were
counted on the necrotic area and were found to be proportional to the necrosis AUDPC.
Nitrogen concentrations in the different leaf parts (inoculated or not) were measured at the
end of the experiment to link senescence and symptoms dynamics to N leaf fluxes. Symptoms
developed following two successive exponential curves throughout leaf life. Nitrogen
application delayed leaf death by 250 degree days but decreased the early rate of necrotic
area growth, while larger inoculation rates resulted in earlier and faster necrotic area growth
rates; no interaction between nitrogen and inoculation rates was observed. Consequently, a
large range of disease dynamics was generated by the nitrogen x inoculation treatments:
however, neither the appearance nor the rate of apical senescence was affected by disease
development. Conversely, the ratio between disease AUDPC’s and leaf duration, and
therefore their damage to photosynthetic activity relative to uninoculated leaves was not
modified by fertilizer rates. Despite the large differences that were generated in GLA dynamics
either through senescence rates with nitrogen treatments or through disease development
with inoculation treatments, the apical senescence rate was never modified by the extent of
Z. tritici-induced necrosis. From a modelling point of view, no impact of disease on apical
senescence has to be accounted for. However, nitrogen as well as inoculation rates interacted
with necrosis development, the determinism of which needs to be deepened.
SPEAKER ABSTRACTS
Thursday 7 April
17:50 - 18:10
BOIXEL Anne-Lise (1)
BERNARD Frédéric (2), LEGEAY Jean (1), SACHE Ivan (1), CHELLE Michaël (2),
SUFFERT Frédéric (1)
(2) ECOSYS, INRA, AgroParisTech,
Response of French Zymoseptoria tritici populations to temperature at
different spatio-temporal scales
Temperature affects epidemiological processes by impacting the development of foliar
pathogens. Our overall objective is to characterize the response of Zymoseptoria tritici to
temperature and its adaptive potential to thermal variations occurring at various spatiotemporal scales. First, at individual scale, we have established that the development of Z. tritici
on adult plant leaves is affected not only by the daily average leaf temperature, but also by its
amplitude. Second, at field population scale, we have studied the impact of thermal seasonal
fluctuations on population dynamics. To do so, we have selected two French Z. tritici
populations, respectively sampled at the beginning (before winter) and at the end (after
spring) of an annual epidemic. Isolates collected at the end of the epidemic were more
aggressive compared to the initial population whether under winter (higher sporulation
capacity) or spring conditions (shorter latency period). Moreover, looking at the phenotypic
variability, we have shown that the population dynamics resulted from a successive selection
of individuals driven by temperature and that a short term adaptation may occur inside
populations at the annual scale. Third, at countrywide population scale, we have investigated
the heterogeneity of temperature responses of French Z. tritici populations. Isolates from six
locations having contrasted annual mean and range of temperature were collected. Then the
thermal performance (considered here through the pathogen multiplication rate) curves of
nine isolates per location were established in vitro. These results have not highlighted a clear
adaptation pattern along temperature gradients, while a differing temperature sensitivity
between Z. tritici populations sampled in contrasting climate zones on a global scale has been
reported in the literature. Thus, these population-based approaches have underlined that
response to temperature may diverge between populations: (i) locally within a year due to a
short term selection resulting from successive climate conditions: (ii) on a global scale which
could be partly explained by genetic differentiation. The variability of thermal performance
curves within and between populations and its epidemiological consequences on disease
(polycyclic) dynamics will be further explored by conducting competition experiments and
through modelling in order to assess the ways in which populations can adapt to thermal
changes.
SPEAKER ABSTRACTS
Friday 8 April
08:40 - 09:00
VALADE Romain (1)
CAPARROY Thomas (1), VITRY Cindy (1), BEAUDOUIN Oriane (1), CONFAIS Johann
(2), GOUT Lilian (3)
(1) Arvalis,-Institut du végétal, Thiverval-Grignon, France (2) BIOGER, INRA, AgroParisTech, ThivervalGrignon, France (3) BIOGER, AgroParisTech, INRA, Thiverval-Grignon, France
Leaf blotch on durum wheat in France: characterization of the species
complex responsible of the disease with a focus on Parastagonospora
nodorum
Leaf blotch, caused by Zymoseptoria tritici and Parastagonospora nodorum is a major disease
complex of wheat worldwide. In France, these diseases have been reported to cause yield
losses up to 50% in bread wheat fields. Yield losses are mainly caused by Z. tritici on bread
wheat. However, little information is available in France for epidemics on durum wheat that
are increasing in prevalence in recent years. We recently conducted a 3 years survey of leaf
blotch on durum wheat and neighbouring bread wheat fields in France. Since Z. tritici and P.
nodorum cause similar symptoms on wheat, we tested the presence of these two fungal
species in infected leaves using microbiological isolation methods and qPCR detection. Z. tritici
was detected in all French regions on both durum wheat and bread wheat. On durum wheat,
P. nodorum was detected in most French regions. On bread wheat P. nodorum was only
quantified at low levels by qPCR. On both durum wheat and bread wheat, P. nodorum
frequently co-occurred with Z. tritici at the leaf and field levels. French durum wheat cultivars
were highly susceptible to the French P. nodorum isolates tested. Bread wheat, triticale and
barley susceptibilities were cultivar and isolate dependant. These results show that control of
leaf blotch on durum wheat, in France, needs to take into account the presence of P. nodorum.
More detailed studies, about its response to current fungicides and about the necrotrophic
effectors present in French populations will help manage leaf blotch on durum wheat.
SPEAKER ABSTRACTS
Session 3: Pathogen genetics and genomics
Plenary lecture
Friday 8 April
09:30 - 10:00
FRIESEN Tim (1)
WYATT Nathan A. (1), BRUEGGEMAN Robert S. (2), FARIS Justin D. (3),
(1)
Department of Plant Science, North Dakota State University, Fargo, USA (2) Department of Plant
Pathology, North Dakota State University, Fargo, ND, USA (3) USDA-ARS, Northern Crop Science Lab,
Cereal Crops Research Unit, Fargo, ND, USA
Unraveling the molecular mechanism of virulence in Pyrenophora teres f.
teres
Net-form net blotch is an economically important foliar disease of barley (Hordeum vulgare)
caused by the necrotrophic fungal pathogen Pyrenophora teres f. teres. Yield losses have been
reported in the range of 10-40% and complete yield loss has been observed under
environmental conditions highly favorable to the pathogen. Little is known as to the molecular
mechanisms involved in the host-pathogen interaction. Therefore, a mapping population was
developed from a cross between two California P. teres f. teres isolates that showed a
differential response on barley lines Rika and Kombar, with 15A being virulent on Kombar and
6A being virulent on Rika. Two virulence QTL conferred by 6A (VR1 and VR2) that contribute
to virulence on Rika and an additional two virulence QTL conferred by 15A (VK1 and VK2) that
contribute virulence on Kombar have been identified. To further investigate the genes
underlying these loci, we have generated a reference-quality assembly based on the Canadian
P. teres f. teres isolate 0-1, and resequencing efforts are underway to obtain near reference
quality assemblies of parental isolates 6A and 15A along with RNA sequencing efforts to
annotate the regions of interest. Previous studies have shown necrotrophic effectors to be
small secreted proteins. Current annotation has predicted a total of 20 genes encoding small
(<50kDa) secreted proteins (SSP) with proximity to the most closely associated markers; two,
two, six, and one of the predicted SSP genes are at the VR1, VR2, VK1, and VK2 loci,
respectively. Further validation and characterization of these genes will give valuable insight
into the barley P. teres f. teres host-pathogen interaction.
SPEAKER ABSTRACTS
Friday 8 April
10:00 - 10:20
BRUNNER Patrick (1)
KRISHNAN Parvathy (1), MCDONALD Bruce (1),
(1) ETH Zurich, Zurich, Switzerland
Widespread signatures of selection at secreted peptidases in a fungal plant
pathogen
Secreted peptidases have been extensively studied for their role as virulence factors.
Pathogens may deliver peptidases into their host cells to derive nutrients or to modify protein
components of the host defense machinery and ultimately suppress defense responses. In this
study we combined transcriptomics, comparative genomics and evolutionary analysis to
investigate the significance of 39 secreted peptidases in the fungal wheat pathogen
Zymoseptoria tritici and its close relatives on wild grasses Z. pseudotritici and Z. ardabiliae.
RNA-seq data revealed that a majority of the secreted peptidases displayed differential
transcription during the course of Z. tritici infection, indicative of life cycle specialization.
Genetic analyses detected widespread evidence of diversifying selection acting on most of the
secreted peptidases. The aspartic endopeptidases emerged as a particularly interesting group,
suggesting a key role in host pathogen co-evolution, host adaptation and pathogenicity. For
example, aspartic endopeptidases showed lineage specific rates of molecular evolution,
suggesting altered selection pressure in Z. tritici after host-specialization on domesticated
wheat. Furthermore, sister genes of aspartic peptidases evolve at different rates, possibly as
a result of sub-, or neofunctionalization after gene duplications. This detailed study of secreted
peptidases in Z. tritici is a further step in determining suitable targets for controlling this
important plant pathogen.
SPEAKER ABSTRACTS
Friday 8 April
10:50 - 11:10
McDONALD Megan(1)
McGINNESS Lachlan (1), HANE James (2), MILGATE Andrew (3), SOLOMON Peter
(1)
(1) The Australian National University, Canberra, ACT, Australia (2) Centre for Crop and Disease
Management, Curtin University, Perth, WA, Australia (3) NSW Department of Primary Industries,
Wagga Wagga, NSW, Australia
Utilizing gene tree variation to identify candidate effector genes in
Zymoseptoria tritici is a host-specific, necrotrophic pathogen of wheat. Infection by Z. tritici is
characterized by its extended latent period, which typically lasts two weeks, and is followed
by extensive host cell death and rapid proliferation of fungal biomass. This work characterizes
the level of genomic variation in 13 isolates for which we have measured virulence on 11
wheat cultivars with differential resistance genes. Between the reference isolate, IPO323, and
the 13 Australian isolates we identified over 800,000 single nucleotide polymorphisms, of
which ~10% had an effect on the coding regions of the genome. Furthermore we identified
over 1700 probable presence/absence polymorphisms in genes across the Australian isolates
using de novo assembly. Finally, we developed a gene tree sorting method that quickly
identifies groups of isolates within a single gene alignment whose sequence haplotypes
correspond with virulence scores on a single wheat cultivar. Using this method we have
identified <100 candidate effector genes whose gene sequence correlates with virulence
towards a wheat cultivar carrying a major resistance gene.
SPEAKER ABSTRACTS
Friday 8 April
11:10 - 11:30
HABIG Michael (1)
QUADE Jakob (1), STUKENBROCK Eva H. (1)
(1) Christian-Albrechts University of Kiel, Environmental Genomics, and Max Planck Institute for
Evolutionary Biology, Kiel, Plön, Germany
Functional Studies on the Accessory Chromosomes of Zymoseptoria tritici
The accessory chromosomes of several fungal plant pathogens like Nectria haemotococca and
Fusarium oxysporum (f. sp. lycopersici) play a role in host specificity and pathogenicity. The
genome of the wheat pathogen Zymoseptoria tritici (syn. Mycosphaerella graminicola)
includes several small accessory chromosomes, however the role of these is so far unknown.
The accessory chromosomes of Z. tritici are characterized by a high degree of
absence/presence polymorphism and structural variation. It has been hypothesized that high
levels of plasticity may enhance rapid adaption to different hosts and environmental
conditions. Nevertheless, the accessory chromosomes contain only very few genes that in
general are silenced or only expressed at low levels during host infection. Functional studies
are needed to obtain insight into the role of genes located on the accessory chromosomes.
We deleted full chromosomes in the reference strain IPO323 to assess their importance for
normal growth and pathogenicity. We generated viable strains in which each of the single
accessory chromosomes were deleted. The deletion frequencies differed significantly among
the individual accessory chromosomes with chromosome 15 being overrepresented and
chromosome 19 underrepresented suggesting that some chromosomes are more stable than
others. The phenotypic consequences of single accessory chromosome deletions were
characterized in vitro and in planta. Overall, our new strain collection provides a valuable
resource for the in-depth assessment of the functional role of accessory chromosomes in this
important wheat pathogen.
SPEAKER ABSTRACTS
Friday 8 April
11:30 - 11:50
MÖLLER Mareike (1)
SCHOTANUS Klaas (1), FREITAG Michael (2), STUKENBROCK Eva (1)
(1) Environmental Genomics, Christian-Albrechts University, Kiel and Max Planck Institute for
Evolutionary Biology, Plön, Kiel, Plön, Germany (2) Department of Biochemistry and Biophysics, Center
for Genome Research and Biocomputing, Oregon State University, Corvallis, USA
Accessory chromosome instability during mitosis and the impact of histone
methylation shown by experimental evolution of Zymoseptoria species
Zymoseptoria tritici is a pathogenic fungus of wheat (Triticum aestivum). The genome of Z.
tritici consists of 21 chromosomes of which the eight smallest chromosomes are classified as
accessory. These chromosomes are highly instable during meiosis and show an increased rate
of rearrangements and repetitive elements as well as an enrichment of heterochromatic
histone marks. To gain insights into the mechanisms involved in stability of the accessory
chromosomes in different field isolates of Z. tritici and a closely related sister species,
Zymoseptoria aradbiliae, we combined epigenetic and evolutionary analyses. Based on studies
in Schizosaccharomyces pombe and cancer cells, we hypothesized that the methylation of
specific histone tails and the resulting changes in chromatin structure could play a role in
chromosome stability in Z. tritici. We therefore created deletion mutants of the
methyltransferases KMT6 and KMT1 in Z. tritici to study the importance of the histone
modifications H3K27me3 and H3K9me3 on genome stability over several mitotic cell divisions.
We conducted an evolution experiment to analyze the influences of prolonged growth in
axenic culture on genome stability in the kmt1 and kmt6 mutants in comparison to wild
type and analyzed the karyotypes of evolved wild type and mutant strains. Prolonged growth
of all Z. tritici isolates led to accessory chromosome losses, while the loss of H3K9me3 in the
kmt1 mutants affected the stability and structure of both core and accessory chromosomes
likely by activation of transposable elements. Based on our results we conclude that the
accessory chromosomes of Z. tritici are highly unstable during mitotic cell divisions and that
loss of H3K9me3 has a genome wide impact on genome stability.
SPEAKER ABSTRACTS
Plenary Lecture
Friday 8 April
11:50 - 12:20
RUDD Jason (1)
KING Robert (1), MOTTERAM Juliet (1)
(1) Rothamsted Research, Harpenden, UK
Functional genomics approaches for unravelling the Zymoseptoria triticiwheat host-pathogen interaction.
Zymoseptoria tritici (syn Septoria tritici and Mycosphaerella graminicola) is a Dothideomycete
fungal pathogen of cultivated wheat, and the causal agent of Septoria tritici blotch (STB)
disease. Despite its agricultural importance, to date only <30 genes have been identified which
contribute to virulence of Z. tritici on wheat. The availability of transformation protocols and
high throughput mutagenesis methods, combined with genome re-sequencing, in planta
transcriptomics and improved genome annotations, enable both forwards and reverse genetic
screens to be performed with the aim of identifying more (and potentially novel) virulence
genes. We have been analysing a library of ~1,200 T-DNA insertion mutants of the reference
Z. tritici isolate IPO323 and a second independent library generated via a different method in
a second fungal isolate. These combined approaches have revealed many new candidate
genes for virulence and identified different biological processes which contribute to this, some
of which are linked to morphogenetic growth changes.
SPEAKER ABSTRACTS
Friday 8 April
13:40 - 14:00
MEHRABI Rahim (1)
MOHAMMADI Naser (2), MOHAMMADI GOLTAPEH Ebrahim (2), MIRZADI
GOHARI Amir (3), SAFAIE Naser (2), KEMA Gert H. J. (3)
(1) Seed & Plant Improvement Institute, Agricultural Research, Education & Extension Organization
(ARREO), Karaj, Iran (2) Department of Plant Pathology, Faculty of Agriculture, Tarbiat Modares
University, Tehran, Iran (3) PRI, Wageningen University, Wageningen, The Netherlands
The ZtVf1 transcription factor regulates development and virulence in the
foliar wheat pathogen Zymoseptoria tritici
The dimorphic fungal pathogen, Zymoseptoria tritici undergoes discrete developmental
changes to complete its life cycle on wheat. Molecular mechanisms underlying morphogenesis
during infection process of Z. tritici is poorly understood. In this study, we have investigated
the role of ZtVf1 gene encoding a transcription factor belonging to C2H2 subfamily. In planta
assays revealed that ZtVf1 is required for virulence. Reduced necrotic lesions and low pycnidia
density within the lesions resulted in significantly reduced virulence of ZtVf1 mutants.
Cytological analysis showed that the impaired virulence of ZtVf1 mutants could be attributed
to a reduced penetration and colonization along with hampered pycnidia differentiation. In
vitro phenotyping showed that ZtVf1 mutation affects hyphal branching and biomass
production suggesting that the reduced tissue colonization by the ZtVf1 mutant might be due
to a lower hyphal branching and less fungal biomass production. In addition, the majority of
substomatal cavities infected by the ZtVf1 mutant were filled with compacted mycelia mat
that did not differentiate into mature pycnidia indicating that the impaired melanization
negatively affected pycnidia formation and maturation. The ZtVf1 might target multiple genes
belonging to different cellular processes whose identification is of eminent interest to increase
our understanding of this pathosystem. Overall, the data provided in this study indicates that
attenuated pathogenicity of ZtVf1 mutant is due to involvement of this gene in the regulation
of both early and late stages of infection.
SPEAKER ABSTRACTS
Friday 8 April
14:00 - 14:20
SIDHU Yaadwinder (1)
CHAUDHARI Yogesh (1), CSUKAI Michael (2), HAYNES Ken (1)
(1) University of Exeter, Exeter, UK, (2) Syngenta UK, Jealotts Hill International Research Centre,
Bracknell, UK.
From tools to functional genomics; elucidating the stealth pathogenesis of
Zymoseptoria tritici, which causes Septoria tritici leaf blotch (STB), is a major threat to global
wheat production. STB can reduce wheat yields by 50% and reducing these losses would make
it possible to meet the food demands of the rising human population. Thus it is crucial to
develop durable STB control measures and for this a comprehensive understanding of the
molecular mechanisms underlying the bi-phasic STB infection cycle is essential. To facilitate
this, we have developed molecular tools to enable medium throughput functional genomics
analyses of Z. tritici. These tools include Z. tritici strains to facilitate highly efficient targeted
genome manipulations, a versatile gene overexpression strategy and regulatable promoters
to provide a tightly controlled gene regulation in Z. tritici. Using these tools we revealed that
the Z. tritici
-(1,3)-glucan synthase (BGS1) gene underpinned cell wall stress tolerance
and was indispensable, thus it could be exploited as a potential drug target. Furthermore,
these tools facilitated an in-depth functional characterization of the glyoxylate cycle and
revealed that this pathway was a key virulence-determining factor in Z. tritici. Analysis of this
pathway revealed that Z. tritici utilized stored lipids and fatty acids, through gluconeogenesis,
to fuel the hyphal growth, which is a prerequisite to initiate STB infection. Therefore, these
tools would revolutionise large-scale functional genomics analyses in Z. tritici.
SPEAKER ABSTRACTS
Friday 8 April
14:20 - 14:40
YEMELIN Alexander (1)
BRAUCHLER Annamaria (2), JACOB Stefan (1), ANDRESEN Karsten (1),
SCHÜFFLER Anja (1), FOSTER Andrew John (1), THINES Eckhard (2)
(1) IBWF, Kaiserslautern, Germany (2) Johannes Gutenberg-Universität Mainz, Institut für
Mikrobiologie und Weinforschung, Mainz, Germany
Identification of novel factors involved in dimorphism and pathogenicity of
Zymoseptoria tritici (syn Mycosphaerella graminicola and Septoria tritici) is the causal agent
of Septoria leaf blotch disease of wheat (Septoria tritici blotch, STB). STB diseases have
increased in incidence over the last few decades, which may be seen as a result of an increased
emergence of strains evolving fungicide resistance. Especially Z. tritici has been referred to as
the most destructive foliar pathogen of wheat in Europe. Z. tritici is considered to be a
dimorphic plant pathogen displaying environmentally regulated morphogenetic transition
between unicellular yeast-like and multicellular hyphal growth. Considering the infection
mode of Z. tritici, the switching to hyphal growth is essential for pathogenicity allowing the
fungus the host invasion through natural openings like stomata. In order to understand the
molecular mechanism behind dimorphic transition and thus to identify novel pathogenicity
associated genes, a forward genetics approach was applied. A previously developed
Agrobacterium tumefaciens-mediated transformation (ATMT) method was used in order to
generate a mutant library by insertional mutagenesis including more than 8000 random
mutants, which were subsequently screened for their ability or deficiency to perform a
dimorphic switch on nutrient-poor media. We identifyed 10 dimorphic switch deficient ATMT
mutants, 9 of which exhibited a yeast-like mode of growth and one predominantly growing
filamentous and producing a high amount of mycelium under different growth conditions.
Four insertion mutants were characterized in detail. Three of them were non-pathogenic and
one mutant exhibited a drastically impaired virulence on whole host plants. Moreover further
phenotypical investigations at macroscopic and microscopic levels, revealed different
pleiotropy of the corresponding mutants, concerning tspore morphology and vegetative
growth behavior under different stress conditions. Using the genome walking approach, the
T-DNA integration sites could be recovered and the disrupted genomic loci of corresponding
mutants were identified and validated by reverse genetics experiments. Finally a
transcriptome analysis by RNA-Seq was performed in order to examine the transcriptional
reprogramming during dimorphic switch. The subsequent gene set enrichment analysis should
provide a substantial research material for further investigation of dimorphism by delivering
a list of the genes involved in the dimorphic switch associated process. With this study we
present four novel and functionally characterized genes, which are involved in the dimorphic
switch of the fungal plant pathogen Z. tritici. Exploring transcriptome data with respect to
differences in gene expression under switch-inducing condition unveils new insights to analyze
dimorphism related processes in Z. tritici.
SPEAKER ABSTRACTS
Friday 8 April
14:40 - 15:00
HESS Michael (1)
SGHYER Hind (1), TELLIER Aurélien (2), HÜCKELHOVEN
MÜNSTERKÖTTER Martin (3), GÜLDENER Ulrich (3),
Ralph
(1),
(1) Phytopathology, Technische Universität München, Freising, Germany (2) Section of Population
Genetics, Technische Universität München, Freising, Germany (3) Institute of Bioinformatics and
Systems Biology, Helmholtz Center Munich, Neuherberg, Germany
Investigating the genetic structure and diversity of the barley pathogen
Ramularia collo-cygni
Ramularia collo-cygni (Rcc) is the biotic factor responsible for the disease Ramularia leaf spot
(RLS) of barley (Hordeum vulgare). The fungus is attracting interest in the scientific community
as a result of the increasing number of economically damaging disease epidemics. To
understand more about its epidemiology, the knowledge of its genetic structure and diversity
is essential. To address its genetic structure, the genome of Rcc (urug2 isolate) was de-novo
sequenced (Illumina HiSeq, paired-end of 500 and 8k libraries) and assembled using AllpathsLG assembler. The finished assembled genome of Rcc is about 32 Mb and is currently to be
found in 78 scaffold (N50 scaffold size 1.9 Mb). The fungal RNA from 6 different conditions,
especially one that mimics the plant environment (Barley Straw Agar) was also sequenced to
help the annotation and to uncover putative genes of interest that might be involved in the
pathogenicity or the fungicide resistances for example. Finally, the complete annotation was
performed using gene predictors (Genmark, Fgenesh, Augustus) and was manually, gene by
gene, corrected using the RNA-seq information. The overall annotation enabled the prediction
of 12,346 genes. As for the RNA-seq data, we had a first look into the functional distribution
of the genes differentially expressed among the different conditions. Among the highly
distributed functional categories (p > 0.05), we find an over-representation of «disease,
virulence factors», «secondary metabolites», «polysaccharide metabolism», oand even
«phenylalanine metabolism». These categories are known to be involved in plant-pathogen
interactions. In a phylogenetic study, we compared orthologue protein sequences of over 40
fungal pathogens to Rcc, ranging from closely related Dothideomycetes to biologically very
different species like Blumeria graminis and Botrytis cinerea. We examined differences in gene
families between species to gain insight of the peculiarities of Rcc. Finally, in a pairwise
comparison to the closest match, Zymoseptoria tritici, the dN/dS ratio per gene was
calculated. Despite the high neutral divergence, among the genes with the 1% highest dN
values, we found genes that are differentially expressed in our RNA-seq data in a condition
that mimics the plant environment. The results of our study enabled us to identify candidate
genes for further studies on the evolution and adaptation of this uprising pathogen.
SPEAKER ABSTRACTS
Session 4: Cell biology and host-pathogen interactions
Friday 8 April
15:00 - 15:20
TAN Kar-Chun (1)
RYBAK Kasia (1), SEE Pao Theen (1), PHAN Huyen (1), LIN Shao-Yu (2), SYME
Robert (1), MOFFAT Caroline (1), CHOOI Yit Heng (3), SOLOMON Peter (2), OLIVER
Richard (1),
(1) Centre for Crop Disease Management, Department of Environment and Agriculture, Curtin
University, Perth, Australia (2) Plant Sciences Division, Research School of Biology, The Australian
National University, Canberra, ACT, Australia (3) School of Chemistry and Biochemistry, The University
of Western Australia, Perth, WA, Australia
A functionally conserved transcription factor class regulates necrotrophic
effector expression and virulence of two major fungal pathogens of wheat
Parastagonospora nodorum is the causal agent of septoria nodorum blotch (SNB) on wheat.
The fungus produces a series of necrotrophic effectors to facilitate infection on hosts that
carry dominant sensitivity/susceptibility genes. Three effector genes - SnToxA, SnTox1 and
SnTox3 are well characterised. Products of these genes interact with wheat Tsn1, Snn1 and
Snn3 dominant sensitivity/susceptibility genes respectively, to mediate necrosis and SNB. The
mechanism of effector gene regulation is not known. In this study, we attempt to identify and
characterise such mechanism(s). We carried out functional analysis of a gene that encodes a
putative GAL4-like transcription factor called PnTf1 by generating knockout mutants through
homologous gene recombination. Infection assays revealed that the tf1 mutant was poorly
pathogenic and does not readily sporulate on Tsn1 and Snn3-only wheat. Pathogenicity of the
tf1 mutant was unaltered on Snn1-only wheat. Chemical complementation with microbiallyexpressed SnToxA and SnTox3 restored wildtype-like virulence and sporulation of the mutant.
We have also demonstrated with RT-PCR that SnToxA and SnTox3 were down-regulated in the
tf1 mutant during infection on a Tsn1/Snn1/Snn3 wheat cultivar. SnTox1 expression was
similar to the wildtype. We have also deleted a PnTf1 ortholog in the Tan spot fungus
Pyrenophora tritici-repentis (Ptr). Similar to P. nodorum PnTf1, PtrTf1 also regulate PtrToxA
and virulence on Tsn1 wheat. This finding highlights a common mechanism in two related
necrotrophic fungi that regulate effector gene expression. We have thus far identified a
putative transcription factor that regulates the expression of two effector genes.
SPEAKER ABSTRACTS
Plenary Lecture
Friday 8 April
15:50 - 16:20
FARIS Justin (1)
USDA, ARS, Northern Crop Science Lab, Cereal Crops Research Unit, Fargo, ND, USA
Genetic dissection of host susceptibility in wheat-necrotrophic pathogen
interactions
Interactions between wheat and the necrotrophic pathogens Parastagonospora nodorum (Pn)
and Pyrenophora tritici-repentis (Ptr), which cause the foliar diseases Septoria nodorum blotch
(SNB) and tan spot, respectively, involve dominant host genes that recognize pathogenproduced necrotrophic effectors (NEs) in an inverse gene-for-gene manner to cause disease.
Over the past decade, we have worked to reveal the identity of wheat NE-sensitivity genes
and have so far cloned two (Tsn1 and Snn1) and have identified candidate genes for a third
(Snn3). Tsn1, which confers sensitivity to ToxA produced by both Ptr and Pn, is a member of
the NB-LRR class of disease resistance-like genes. Snn1 recognizes the Pn NE SnTox1 and is a
wall-associated kinase, which sometimes serve as pathogen recognition receptors associated
with disease resistance. These results suggest necrotrophic specialists such as Ptr and Pn use
NEs to exploit pathways often associated with resistance to biotrophs. So far, it appears that
genetic variation in the wheat-Pn system mostly involves host gene-NE interactions (nine have
been identified), but the situation in the wheat-Ptr system is more complex. Whereas the
Tsn1-ToxA interaction is consistently associated with disease in the wheat-Pn system, we have
found that it is background-dependent in the wheat-Ptr system. We have also identified a
major dominant race-nonspecific tan spot resistance gene on wheat chromosome arm 3BL.
Therefore, both resistance and susceptibility genes are likely involved in the wheat-Ptr system.
This work has shed light on the mechanisms associated with necrotrophic effector triggered
susceptibility, but has also revealed that wheat-necrotrophic pathogen interactions may be
more complicated than once thought.
SPEAKER ABSTRACTS
Friday 8 April
16:20 - 16:50
KETTLES Graeme (1)
KANYUKA Kostya (1), RUDD Jason (1)
Necrotrophic effectors from Zymoseptoria tritici
Zymoseptoria tritici is amongst the most prevalent and damaging fungal pathogens of wheat
in Europe. During early wheat leaf colonisation, there is minimal induction of host defence
responses. Later, there is a switch to necrotrophy, accompanied by defence gene induction
and host cell death. Our current model for Z. tritici infection suggests that after an initial
effector-mediated evasion of host responses by stealth, the fungus then deploys other
effectors (necrotrophic) which interact with host susceptibility (S) proteins to induce cell death
and enhance pathogen colonisation. To understand the molecular mechanisms underlying Z.
tritici infection, we identified ~100 putative necrotrophic effectors that show peak expression
at the onset of necrotrophy during infection of susceptible wheat. We cloned and expressed
64 candidates in leaves of the model plant Nicotiana benthamiana using Agrobacteriummediated transient expression. This screen identified 15 proteins that induced cell death or
chlorosis in this non-host species. Of these 15, the majority require localisation to the
apoplastic space for their activity and many induce symptoms in a light-dependent manner.
We are currently using heterologous protein expression systems to investigate the
interactions between these candidate effectors and the wheat immune system to unravel
their role in virulence. Our most recent findings will be presented.
SPEAKER ABSTRACTS
Friday 8 April
16:50 - 17:10
MIRZADI GOHARI Amir (1)
MEHRABI Rahim (2), ZAMANI Elham (3), ROBERT Olivier (4), BOEREN Sjef (5),
KILARU Sreedhar (6), SCHUSTER Martin (6), STEINBERG Gero (6), DE WIT Pierre
(7), KEMA Gert (8), AGAH INCE Ikbal (5)
(1) Department of Plant Protection, College of Agriculture, University of Tehran, Plant Pathology
Building, Karaj, Iran, , (2) Seed and Plant Improvement Institute, Karaj, Iran, (3) Department of Plant
Pathology, Tarbiat Modares University, Tehran, Iran, (4) Bioplante, Florimond Desprez, Cappelle-enPévèle, France, (5) Laboratory of Biochemistry, Wageningen University, Wageningen, The Netherlands,
(6) School of Biosciences, University of Exeter, Exeter, UK, (7) Laborotory of Phytopathology,
Wageningen University, Wageningen, The Netherlands (8) PRI, Wageningen University, Wageningen,
The Netherlands
Identification and functional characterization of putative (a)virulence factors
in the fungal wheat pathogen Zymoseptoria tritici
Zymoseptoria tritici (Desm.) Quaedvlieg & Crous is the causal agent of Septoria tritici blotch
(STB), which is a devastating foliar wheat disease worldwide. It is responsible for significant
yield losses occurring annually in all major wheat-growing areas and threatens global food
security. Upon infection, the fungus secretes a repertoire of proteins functioning as virulence
or avirulence factors to suppress or circumvent plant responses. The identification and
characterization of such proteins provide a better understanding of the Z. tritici lifestyle and
pathogenesis that eventually contributes to designing new and effective disease management
strategies. Initially, we functionally investigated the biological role of the Wor1 ortholog
ZtWor1 in Z. tritici and our results show that it is involved in pathogenicity, regulates the
expression of small-secreted proteins and is most likely part of the cAMP signaling pathway
that plays a pivotal role in many cellular processes. Additionally, we demonstrated that Z.
tritici produces cytoplasmic and an extracellular catalase peroxidases, encoded by the genes
ZtCpx1 and ZtCpx2, respectively, which are crucial for full virulence. Eventually, we combined
bioinformatics, genetic mapping and RNAseq data for effector discovery in Z. tritici.
SPEAKER ABSTRACTS
Friday 8 April
17:10 - 17:30
SANCHEZ VALLET Andrea (1)
MEILE Lukas (1), STEWART Ethan (1), CROLL Daniel (1), McDONALD Bruce (1)
(1) Dep. of Environmental Systems Science, ETH, Zurich, Switzerland
Zymoseptoria tritici pathogenicity is determined by isolate specific virulence
factors
Zymoseptoria tritici is a major pathogen of wheat around the world and the causal agent of
septoria tritici blotch. Understanding the molecular basis of Z. tritici virulence and its genetic
regulation will aid to design better control methods. However, to date only a few virulence
factors have been characterized by means of gene disruption. Remarkable differences in
virulence levels and in host specificity occur among Z. tritici isolates. Therefore, exploring the
genetic bases of phenotypic variability is a promising strategy to identify new virulence
factors. In fact, a single quantitative trait locus (QTL) for virulence was identified to explain the
genetic differences between a highly virulent (3D7) and a non-virulent (3D1) isolate. Gene reannotation of the QTL-region in the 3D7 genome identified 37 candidate genes, including 5
encloding putative effectors and a major facilitator superfamily transporter. Interestingly, the
genomic region where the QTL was mapped is rich in tranposable elements and the synteny
between the parental isolates is not conserved. Two big insertions of around 30 and 40 kb
were identified in 3D7, but not in the 3D1 genome. Two genes encoding two highly
polymorphic putative effectors were identified in between the two regions. The localization
of these two genes in a genomic region undergoing rearrangements points them as candidate
effector genes of Z. tritici.
SPEAKER ABSTRACTS
Friday 8 April
17:30 - 17:50
PALMA-GUERRERO Javier (1)
MA Xin (1), ZALA Marcello (1), TORRIANI Stefano (2), CROLL Daniel (1),
McDONALD Bruce (1)
(1) Plant Pathology Group, ETH Zurich, Zurich, Switzerland (2) Syngenta Crop Protection AG, Stein,
Switzerland
Transcriptional profiling of four Zymoseptoria tritici isolates differing in
virulence.
Zymoseptoria tritici is an ascomycete fungus that causes Septoria tritici blotch (STB), an
important foliar disease on wheat. Z. tritici infects plants through stomata, rather than by
direct penetration, and it exhibits a long latent period of up to 2-3 weeks following infection.
After this latent period the fungus induces necrosis on the plant tissue corresponding with an
increase in fungal biomass. The mechanisms involved in activating necrosis remain unknown.
Z. tritici is a highly polymorphic species showing significant intraspecific variation for virulence.
Our aim was to use this natural variation between isolates to identify genes involved in
virulence. We generated a deep transcriptome sequencing dataset spanning the entire timecourse of infection of four Z. tritici strains isolated from the same region but showing different
levels of virulence. By comparing the transcriptional profiles of the four isolates at different
time points we found that major components of the fungal infection transcriptome were
conserved among the four strains. However, several genes showed strongly differentiated
transcriptional profiles among isolates. Our analyses showed that heterogeneity in
transcriptomes among isolates may explain some of the considerable variation in virulence
and host specialization found within the species. We generated a list of genes that may play
important roles in infection according to their differential expression profiles. Functional
characterization of selected genes is now in progress.
SPEAKER ABSTRACTS
Zymoseptoria genome annotation workshop
Friday 8 April
17:50 - 18:05
KING Robert (1)
RUDD Jason (1), KANYUKA Kostya (1)
A detailed manual curation of the Zymoseptoria tritici IPO323 genome
coupled with RNAseq analysis on susceptible and resistant wheat
Functional and comparative genomics based projects are dependent upon the availability of
a genome sequence of the organism in question and an accompanying genome annotation.
The quality of the annotation can have numerous downstream effects on the research, such
as improving prediction of SNP consequences to filter results of interest. However, if a gene
model is inaccurate or not present in the annotation then this data may be overlooked or
misinterpreted. The fungus Zymoseptoria tritici is an important foliar pathogen of wheat. A
complete genomic reference sequence is available for Z. tritici isolate IPO323, however careful
inspection of the three currently available genome annotations from JGI (10,933 genes),
Rothamsted Research (10,688 genes) and Max Planck Institute (11,839 genes) reveals that
each of these contains a number of inaccurately predicted gene models. For example, some
gene models appear to be lacking either start or stop codon, and some have two physically
closely linked genes miss-annotated as one. Moreover, several gene models can only be found
in one of the three genome annotations but not in the other two. Here we present results of
a comprehensive re-annotation of Z. tritici IPO323 genome followed by its manual curation.
To achieve this, the three earlier genome annotations were merged together with a fourth,
new annotation that we produced using Maker2 in combination with new transcript and
protein supporting evidences. We identified a large number of gene models that were missed
or miss-annotated in previous genome annotations. Our resulting annotation consists of
13,862 gene models with 899 of those representing genes encoding secreted proteins with
high confidence, which is a 55% increase (317 new genes) on the JGI annotation set of 582
and 7.5% increase (125 new genes) on the Max Planck Institute set of 774 genes. Using this
new annotation we generated and compared RNA-seq data from Z. tritici infecting wheat
leaves of a resistant and susceptible cultivar. We found 352 gene models uniquely upregulated
on the resistant cultivar. These genes represent an important subset for further investigation
of pathogen interaction with host defences.
SPEAKER ABSTRACTS
Zymoseptoria genome annotation workshop
Friday 8 April
18:05 - 18:20
PEDRO Helder (1)
(1) European Bioinformatics Institute, Wellcome Trust Genome Campus , Hinxton, UK
Community annotation using WebApollo for PhytoPath species
PhytoPath (http://phytopathdb.org) is a web portal for data for phytopathogenic species
bringing together genomic information from Ensembl Fungi and phenotypic information from
PHI-base. WebApollo is being adopted at PhytoPath as the decentralized tool of choice for
genome curation. Web Apollo is a web-based client providing a graphical, drag-and-drop user
interface that does not require local installation, and provides tools to edit genome
annotation, create new genes, transcripts and other genomic elements, and change exon
boundaries. I will give an introduction to Web Apollo and demonstrate its application for the
validation and re-annotation of Botrytis cinerea gene models.The adoption of this tool by
communities provides a rapid model for the correction of gene models in Ensembl Fungi, and
I will outline the current workflow for integration of user annotated genes into the current
reference gene set in use by Ensemble Fungi and PhytoPath.
SPEAKER ABSTRACTS
Saturday 9 April
08:40 - 09:00
AVROVA Anna (1)
FRANCO Barbara (1), BEREPIKI Adokiye (1), BIRCH Paul (2), KANYUKA Kostya (3),
(1) James Hutton Institute, Dundee, UK (2) University of Dundee, Dundee, UK (3) Rothamsted Research,
Harpenden, UK
A novel fungal PAMP identified in Rhynchosporium commune is recognised in
dicots
Rhynchosporium commune is by far the most damaging and costly pathogen of both spring
and winter barley in the UK. Despite regular fungicide applications R. commune costs the UK
economy around £7.2 million per year. Cultivar resistance is an important part of disease
management for this pathogen, however continued use of major resistance genes Rrs1 and
Rrs2 has led to rapid breakdown of these resistances. Plants have evolved innate immune
responses that are induced upon recognition of pathogen-associated molecular patterns
(PAMPs). PAMPs are detected by plant cell surface localized pattern-recognition receptors
(PRRs) and elicit PAMP-triggered immunity (PTI). Sequencing of the R. commune
transcriptome from an early time point during infection revealed a highly abundant transcript
encoding a novel small secreted fungal protein, which we called Rc1. It is most highly upregulated at three days post inoculation with R. commune. Rc1 and its homologues from
different fungal species, including Botrytis cinerea and Sclerotinia sclerotiorum, produced
using Pichia pastoris, exhibit PAMP activity triggering cell death in solanaceous and Brassica
species, but not in monocots. Using virus-induced gene silencing (VIGS) of known components
of PTI in Nicotiana benthamiana, Rc1-triggered cell death was shown to be BAK1 and SGT1
dependent. In contrast, CMPG1 was shown not to be involved in response to Rc1 recognition.
Transient expression of truncated versions of Rc1 protein in N. benthamiana indicated that
the N-terminal region of the protein is essential for the recognition that triggers plant cell
death. Identification of the plant receptor involved in Rc1 recognition in dicots will provide a
valuable resource for engineering non-host resistance in monocots.
SPEAKER ABSTRACTS
Saturday 9 April
09:00 - 09:20
FONES Helen (1)
EYLES Chris J (1), GURR Sarah J (1)
(1) Department of Biosciences, University of Exeter, Exeter, UK
A role for random, humidity-dependent epiphytic growth in infection of
wheat by Zymoseptoria tritici
Zymoseptoria tritici is the causal agent of Septoria blotch disease inwheat. The epidemiology
of this disease shows that leaf wetness is important in establishing infection. Unusually for a
fungal plant pathogen, Z. tritici induces no symptoms for around ten days, despite penetration
of leaves, via stomata, within 24-72 hours. However, this assertion of early penetration is
derived from studies whose primary aim was to elucidate the manner, rather than timing of
entry. Conditions which favour fungal entry, including high humidity, leaf wetness and
darkness post inoculation were combined with high inoculum density, were therefore used to
reassess the process of infection. Here, we use a GFP-tagged Z. tritici strain for minimally
invasive confocal microscopy to study the fungus on the leaf surface. The average time for an
individual fungal spore to achieve penetration was ten days, with penetration events
accurately captured by a simple random model of fungal growth. Growing wheat plants under
higher humidity increased the rate of hyphal emergence, decreased the average time to
penetration, and increased the final number of pycnidia produced. Wounded leaves were
more susceptible to infection and displayed pycnidia earlier after inoculation. We conclude
that Zymoseptoria is capable of surviving as an epiphyte on wheat and has not developed
sophisticated surface sensing or stoma-seeking mechanisms. This epiphytic growth may
explain why Zymoseptoria risk is influenced by weather conditions. There are also
implications of prolonged epiphytic growth for control, and for interpretation of observed low
in planta growth, metabolic quiescence and evasion of plant defences during the symptomless
phase of infection.
SPEAKER ABSTRACTS
Saturday 9 April
9:20 - 9:40
MEAD Oliver (1)
(1) Australian National University, Canberra, Australia
Gamma-aminobutyric acid: A regulator of asexual reproduction and
pathogenicity in the wheat pathogen, Parastagonospora nodorum.
Gamma-aminobutyric acid (GABA) is a non-proteinaceous amino acid produced in a chemical
shunt from the Krebs cycle. This molecule and its associated pathway have long been known
in animal and plant systems as a neurotransmitter and abiotic stress regulator respectively.
Through the GABA shunt alpha-ketoglutarate is drawn from the Krebs cycle and returned as
succinate, bypassing a key ATP producing reaction. Despite the expense at which GABA is
produced, and the ubiquity in fungi of the enzymes required for its metabolism, its function is
yet to be determined. The dothideomycete Parastagonospora nodorum is a wheat pathogen
and the causal agent of the disease Septoria Nodorum Blotch. This disease is prevalent
worldwide, causing significant economic losses to growers in Europe, the U.S.A, the Middle
East and Australia. This project utilized the amenability of P. nodorum to genetic
transformation and ‘Omics techniques to investigate the role of GABA in a fungal plant
pathogen. Essential enzymes in the GABA pathway were disrupted, which dramatically
reduced virulence and increased the growth rate of P. nodorum. Conversely, exogenous
addition of GABA to fungal growth media induced a state of hyper sporulation. To explore the
influence of GABA on sporulation further, a combined transcriptomic and metabolomic
approach was employed. Here we describe the changes of gene expression and metabolites
in important sporulation pathways that are induced when GABA is added to fungal growth
media.
SPEAKER ABSTRACTS
Saturday 9 April
09:40 - 10:00
HAUEISEN Janine (1)
GRANDAUBERT Jonathan (1), STUKENBROCK Eva (1)
(1) Environmental Genomics, Christian-Albrechts University of Kiel andMax Planck Institute for
Evolutionary Biology, Kiel, Plön, Germany
Combination of confocal microscopy and RNAseq reveals dramatic inter- and
intra-species diversity of Zymoseptoria spp. during wheat infection
Zymoseptoria tritici (syn. Mycosphaerella graminicola) is a global pathogen specialised to
infect wheat in homogeneous agroecosystems. However, genotypes, karyotypes and
phenotypes of field isolates exhibit an amazingly high degree of intra-species diversity. It has
been shown that Z. tritici originated in the Middle East where is also the habitat of its closest
relatives Z. pseudotritici and Z. ardabiliae. These fungi are endemic in natural grasslands in the
north of Iran and have been isolated from leaves of diverse wild grasses. Due to their
adaptation to different hosts and environments these Zymoseptoria species provide an ideal
model to address questions relating to speciation and host specialisation of fungal pathogens.
We studied and compared the infection development of the three species to assess how
adaptive evolution has shaped infection programs and processes. We inoculated wheat leaves
with different isolates and analysed their infection morphology and development by confocal
laser scanning microscopy. We combined this with stage-specific RNAseq to capture dynamics
in fungal transcription. Microscopic analyses identified four distinct Z. tritici core infection
stages on wheat (A: Infection development, B: Biotrophic growth, C: Lifestyle transition and
D: Necrotrophy and asexual reproduction). During the individual stages certainly morphology
and infection development clearly differed between Z. tritici isolates. However, Z. pseudotritici
and ardabiliae isolates did not colonize living wheat leaves further than substomatal cavities.
Infection hyphae were arrested and no infection symptoms developed. Differential gene
expression analyses based on RNAseq showed that Z. tritici gene expression is dynamic during
infection. Within the isolates ~10% of the genes followed a stage-specific transcription profile
between stages A and B. They are significantly enriched in genes encoding secreted proteins
and putative effectors. However, only 85 of them are differentially expressed in all studied Z.
tritici isolates but 32 encode secreted proteins. We reason that these shared stage-specific
genes contribute to the Z. tritici core transcription program important for infection stages and
progress and thereby are involved in specialisation to wheat. Currently, we are investigating
the expression profiles of Z. pseudotritici and ardabiliae on wheat to determine speciesspecific expression of orthologs and species-specific genes in the three Zymoseptoria species.
SPEAKER ABSTRACTS
Saturday 9 April
10:00 - 10:20
RAY Rumiana (1)
AJIGBOYE Olubukola (1), JAYAWEERA Dasuni (1), BEECH Daniel (1), FOULKES John
(1), MURCHIE Erik (1)
(1) University of Nottingham, Sutton Bonington, UK
Chlorophyll fluorescence allows the rapid differentiation of varietal responses
to Zymoseptoria tritici in winter wheat
Zymoseptoria tritici, the causal agent of Septoria tritici blotch (STB) disease is considered the
most damaging foliar pathogen of winter wheat in temperate Europe. A major challenge for
the effective control of the disease and the rapid discrimination of resistant genotypes is the
early detection of host response to pathogen infection. The present study was undertaken to
identify chlorophyll fluorescence (CF) parameters that can quantify changes in photosystem II
(PSII) associated with plant responses to infection by Z. tritici in field grown winter wheat. Fast
CF (OJIP) transients were analyzed with the JIP-test to determine changes in PSII
photochemistry of different wheat genotypes. Measurements on asymptomatic leaves
showed that changes related to maximum efficiency of PSII photochemistry (Fv’/Fm’) as well
as flux of energy dissipated (DIo/RC), trapped (TRo/RC), or absorbed (ABS/RC) per active
reaction centres were significant to detect early biotic stress and quantify genotype responses
and the effectiveness of fungicide treatment for disease control.
SPEAKER ABSTRACTS
Session 5: Host genetics and resistance breeding
Plenary Lecture
Saturday 9 April
10:50 - 11:20
SADANANDOM Ari (1)
(1) School of Biological and Biomedical Sciences, Durham University, Durham , UK
Host defences against Septoria tritici blotch
A distinguishing feature of Septoria leaf blotch disease in wheat is the long symptomless
growth of the fungus amongst host cells followed by a rapid transition to necrotrophic growth
resulting in disease lesions. Global reprogramming of host transcription marks this switch to
necrotrophic growth. However no information exists on the components that bring about host
transcriptional reprogramming. Gene-silencing, confocal-imaging and protein-protein
interaction assays where employed to identify a Plant HomeoDomain (PHD) domain protein,
TaR1 in wheat that plays a critical role during the transition from symptomless to necrotrophic
growth of Septoria. TaR1-silenced wheat show earlier symptom development upon Septoria
infection but reduced fungal sporulation indicating that TaR1 is key for prolonging the
symptomless phase and facilitating Septoria asexual reproduction. TaR1 is localised to the
nucleus and binds to wheat Histone 3. Trimethylation of Histone 3 at lysine 4 (H3K4) and
lysine 36 (H3K36) are found on open chromatin with actively transcribed genes, whereas
methylation of H3K27 and H3K9 are associated with repressed loci. TaR1 specifically
recognises di- and trimethylated H3K4 peptides suggesting that it regulates transcriptional
activation at open chromatin. We conclude that TaR1 is an important component for the
pathogen life cycle in wheat that promotes successful colonisation by Septoria.
SPEAKER ABSTRACTS
Saturday 9 April
11:20 - 11:40
STEUERNAGEL Burkhard (1)
WULFF Brande B. H. (1)
(1) John Innes Centre, Norwich Research Park, Norwich, UK
Rapid cloning of genes in wheat using targeted sequence capture
We present a method to clone wheat genes that can be phenotypically defined by
mutagenesis (typically by screening for loss-of-function mutants). High throughput
sequencing of the wildtype parent and several independently derived mutants belonging to
the same complementation group allows us to identify induced, causative mutations in a
single candidate gene. We use various complexity reduction approaches, such as targeted
sequence capture, to reduce the cost and computational load of sequencing and analysing
multiple individuals. We have demonstrated the feasibility of our method on three stem rust
resistance genes. As most resistance genes cloned to date belong to a family of genes encoding
for proteins with a nucleotide binding site domain and leucine-rich repeats (NB-LRRs) we
designed an NB-LRR exome capture library based on known NB-LRR genes in Triticeae. We
first used our exome capture library in a proof-of-concept experiment to re-clone Sr33 by
performing resistance gene enrichment sequencing (RenSeq) on previously defined mutants
of Sr33. We next cloned two novel genes, Sr22 and Sr45, and subsequently validated these by
transgenic complementation. Our method of combining RenSeq with EMS mutagenesis does
not rely on positional fine mapping nor does it require a BAC library. It therefore provides an
excellent complementary approach to map-based cloning. Our proof of concept focuses on
NB-LRR–type genes, however we see large potential in applying this to various other gene
families.
SPEAKER ABSTRACTS
Saturday 9 April
11:40 - 12:00
KROJ Thomas (1)
MOREL Jean-Benoit (1)
(1) BGPI, INRA, , Montpellier, France
Integration of decoy domains derived from protein targets of pathogen
effectors into plant immune receptors is frequent and widespread
Receptors of the class of nucleotide-binding and leucine-rich repeat domain (NLR) proteins
play a crucial role in plant immunity. They recognize effectors in the cytosol of host cells by
direct physical binding, or indirectly by interacting with other host proteins that are modified
by effectors or by binding complexes of host proteins and effectors. These recognized host
proteins can be either virulence targets of the effectors or decoys that mimic virulence targets.
Recent research showed that NLRs can contain additional domains besides canonical NB-ARC
(nucleotide-binding, adaptor shared by APAF-1, R proteins, and CED-4) and leucine-rich repeat
(LRR) domains and that these additional domains can act as integrated decoys recognizing
effectors from pathogens. Proteins homologous to such integrated domains are suspected to
be effector targets and involved in disease or resistance. We analyzed 31 entire plant genomes
to identify putative integrated decoy domains in NLR proteins using Interpro search. This
showed that unusual domains are integrated with a mean frequency of 3.5% into NLRs. NLRs
carrying unusual domains were identified in all analyzed plant lineages, including mosses, and
correspond to all major groups of NLRs. A huge number of functionally diverse domains were
found in NLRs and they are integrated at different positions, indicating that the integration of
unusual domains has occurred frequently and repeatedly during plant evolution. All these
features support the model that these unusual domains in NLRs represent integrated decoys
that allow plants to detect pathogen effectors that target other proteins carrying such
domains. The integrated decoy model is therefore a powerful concept to identify new proteins
involved in disease resistance and further in-depth examination of integrated domains in NLR
proteins promises to unravel many new proteins of the plant immune system.
SPEAKER ABSTRACTS
Saturday 9 April
12:00 - 12:20
TARANTO Adam (1)
McDONALD Megan C. (1), SOLOMON Peter S. (1)
(1) Australian National University, Canberra, Australia
Cross-cultivar transcriptomics: A novel method for comparing pathogeninduced gene expression between non-model and polyploid host varieties.
Following infection, gene expression of a plant host can reveal pathways and processes
targeted by a successful fungal pathogen. Equally, plant genes deployed in a successful
defence response may betray fungal weaknesses, and provide clues for breeding durable
resistance. Accurate prediction of differentially expressed genes between cultivars relies on
identification of equivalent transcripts. For many crop species reference genomes are not
available and generation of near-isogenic lines is impractical; necessitating the use of de novo
transcriptome assemblies. Traditional identity-based clustering methods face a trade-off in
polyploid species; strict clustering allows true divergent homologues between cultivars to
group together, but risks over-clustering of biologically relevant homeologs, paralogues and
splice variants. We employ a recently developed hierarchical, shared-read, clustering method
to assign equivalent transcripts between independently assembled de novo transcriptomes.
This method is superior to pooled-read assemblies, and allows preservation of splice-variants
with distinct expression profiles, while minimising homeologue collapse. Two allohexaploid
wheat (Triticum aestivum) cultivars, with differential susceptibility to the necrotrophic fungal
pathogen Parastagonospora nodorum were infected, and their transcriptomes sequenced.
This work highlights several known components of anti-fungal plant defence at play in
susceptible and non-susceptible varieties, as well as suggesting a role for novel candidates.
SPEAKER ABSTRACTS
Saturday 9 April
12:20 - 12:40
SAINTENAC Cyrille (1)
KANYUKA Kostya (2), LEE Wing Sham (2), CAMBON Florence (1), KING Robert (3),
PHILLIPS Andy (2), UAUY Cristobal (4), HAMMOND-KOSACK Kim (2), LANGIN
Thierry (1)
(1) GDEC, INRA-UBP, Clermont-Ferrand, France (2) Plant Biology and Crop Science Department,
Rothamsted Research, Harpenden AL5 2JQ, UK (3) Computational and Systems Biology Department,
Rothamsted Research, Harpenden AL5 2JQ, UK
Cloning of Stb6 – the first gene conferring race-specific resistance against the
Septoria tritici blotch disease
Septoria tritici blotch (STB) is an important foliar disease of wheat resulting from infection by
the ascomycete fungus Zymoseptoria tritici, belonging to the family Mycosphaerellaceae. STB
is encountered in all wheat growing areas of the world. Disease management is achieved
through the use of fungicides and resistant wheat cultivars. A total of 21 major genes
conferring isolate-specific resistance as well as 89 resistance QTLs have been characterized
genetically. To date however, none of these have as yet been cloned and mechanisms of
resistance remain poorly understood. Here, we report isolation of the Stb6 gene controlling
resistance to Z. tritici isolate IPO323 in many commercial wheat genotypes. First, we finemapped Stb6 to an interval < 0.7 cM genetic interval. Subsequent sequence analysis revealed
five genes related at the sequence level present at the Stb6 locus. Two of the closely linked
genes, separated from others by recombination events, were considered to be the best
candidates for Stb6. Using VIGS and TILLING we were able to demonstrate that one of these
candidates corresponds to Stb6. Genetic complementation experiments are underway, and
initial characterization of resistance in T1 lines will be presented. Based on the analysis of the
Stb6 domains structure, we will also discuss potential mechanisms of Stb6-directed resistance.
Stb6 is the first gene to be cloned and characterized from any plant species that confers
resistance to the STB disease caused by Z. tritici.
SPEAKER ABSTRACTS
Saturday 9 April
14:00 - 14:20
BROWN James (1)
JUDGE Chris (1)
(1) John Innes Centre, Norwich, UK
A trade-off between yield and Septoria resistance in wheat
Genes conferring lower severity of Septoria tritici blotch, lower yield, smaller leaves and earlier
senescence were mapped to the same quantitative trait locus (QTL) in the wheat genome. In
an association genetics study, this QTL was the most important contributor to Septoria
resistance in UK wheat varieties and its role in reducing Septoria symptoms was confirmed in
a biparental cross. Near-isogenic lines (NILs) were developed to study its effect on Septoria
and on the relationship between Septoria and yield. In pathology tests in which seedlings or
adult plants were inoculated with Zymoseptoria tritici, there was no variation within the pairs
of NILs, implying that genes at this locus do not control foliar resistance to Z. tritici. The
hypothesis that the locus contains genes for traits which may influence disease escape and
yield components was tested. This was supported by data on the NILs from epidemiology
experiments in which the amount and type of watering was controlled, and by detailed
observations of phenotypes in field plots. Smaller leaves and faster senescence were both
implicated in reducing Septoria severity, but their relative importance differed between
experiments. It is concluded that this important Septoria QTL is involved in disease escape
rather than resistance and that there is genotype-by environment interaction in the
expression of traits which map to this QTL. Additionally the escape traits may also have
detrimental effects on yield components which map to this region. A goal for plant breeding
is to use other sources of genes for yield or for durable resistance to Septoria, to mitigate the
undesirable trade-offs associated with this locus.
SPEAKER ABSTRACTS
Session 5: Host genetics and resistance breeding Breeding
Saturday 9 April
14:20 - 14:40
FRANCKI Michael (1)
WALKER Esther (1), LI Dora (2)
(1) Department of Agriculture And Food Western Australia, South Perth, Western Australia, Australia
(2) State Agricultural Biotechnology Centre, Murdoch University, Murdoch, Western Australia, Australia
SNP mapping and wheat genome sequence analysis identified linked QTL and
genes that respond differently to SNB across environments.
Septoria nodorum blotch (SNB) caused by Parastagonospora nodorum is a significant
necrotrophic fungal disease of wheat in Western Australia and other regions of the world. The
disease has a significant effect on grain yield when the pathogen infects the flag leaf and
glumes. Fungicide applications have limited use in disease management and there are only a
few Australian wheat cultivars that have moderate resistance in adult plants. Breeding
provides an alternative strategy for disease management but requires the exploitation of a
wider source of germplasm with suitable adult plant resistance to SNB. Wheat accessions from
the primary gene-pool of global collections were evaluated for disease response inWestern
Australian and other environments and quantitative trait loci (QTL) were identified for flag
leaf resistance on chromosomes 1B, 2A, 2D and 5B and glume resistance on chromosomes 2D
and 4B. High resolution genetic mapping using the wheat 90K Infinium SNP chip identified
8,000-16,000 additional markers per map, increasing the density of markers spanning each
QTL interval. In some instances, the high density SNP markers identified linked QTL in the
same chromosomal regions, indicating distinct clusters of concomitant disease-related genes
in the host responds differently to pathogen infection across environments. Nevertheless, the
regions containing linked QTL and associated genes are being introgressed into adapted wheat
where SNP markers and high-throughput screening selected chromosomal blocks of disease
related genes to identify the best single and combined QTL for improved flag leaf and glume
resistance. The linked QTL controlling trait expression and the availability of the wheat
genome survey sequence provided an opportunity to identify causal candidate genes
contributing to flag leaf and glume resistance in different environments. SNP sequences
within QTL intervals were aligned with the wheat genome survey sequence and analysis of the
annotated regions identified in excess of 600 gene sequences within some QTL intervals, with
numerous genes related to disease resistance, defence response or related signal transduction
pathways. Therefore, it appears that QTL intervals contain clustered network of many disease
related genes that may contribute varying responses to pathogen infection under different
environmental conditions.
SPEAKER ABSTRACTS
Saturday 9 April
14:40 - 15:00
GOODWIN Stephen (1)
(1) USDA-Agricultural Research Service / Purdue University, West Lafayette, USA
Revised map locations for the Stb2 and Stb3 genes for resistance to Septoria
tritici blotch on chromosome arms 1BS and 7AS of wheat
Septoria tritici blotch, caused by the ascomycete fungus Zymoseptoria tritici (syn.
Mycosphaerella graminicola and Septoria tritici), is an economically important disease that
occurs in most wheat-growing areas worldwide. Although chemical control is effective, the
fungus has developed resistance to the commonly used fungicides making host resistance a
more attractive option. At least 17 major genes for resistance have been named and mapped
but most have a low number of linked molecular markers and have not been used extensively
in breeding programs. The Stb2 and Stb3 genes for resistance were mapped previously to
wheat chromosome arms 3BS and 6DS, respectively. To identify more molecular markers
linked to these genes, additional marker loci were screened on the parents and mapped in the
same progeny of crosses when polymorphic. However, the new markers were not linked to
the resistance loci. Instead, for gene Stb2 from the cultivar Veranopolis, a new map location
was identified on wheat chromosome arm 1BS that was flanked by microsatellite loci
Xwmc406 and Xbarc008 at genetic distances of approximately 6 and 5 cM, respectively.
Microsatellite locus Xwmc230 also was closely linked. This region is near the location of the
previously mapped resistance gene Stb11. The three new linked co-dominant markers could
be useful for moving Stb2 into adapted germplasm. Gene Stb3 was relocated to chromosome
arm 7AS and the resistance gene co-segregated with molecular locus Xwmc83. Its new map
location was flanked by microsatellite loci Xcfa2028 and Xbarc222 at genetic distances of 12.4
and 2.1 cM, respectively, and was validated in additional crosses to confirm the linkages. This
revised location of Stb3 is different from published map locations of other STB resistance
genes in hexaploid wheat, but is approximately 20 cM proximal to a gene for resistance to STB
that mapped to the short arm of chromosome 7Am in the diploid wheat relative Triticum
monococcum. Gene Stb3 was originally from the cultivar Israel 493, which has a very early,
short spring growth type. So far it confers near immunity in most progeny lines, although its
effectiveness in the field has yet to be proven. Gene Stb2 also has a very strong resistance
phenotype which appears more leaky in progeny. Due to their strong resistance, both of these
genes likely will be broken down if used singly in wheat cultivars, but they may be useful in
combination with other resistance genes.
SPEAKER ABSTRACTS
Saturday 9 April
15:00 - 15:20
HOURCADE Delphine (1)
GOUACHE David (1), BEAUCHENE Katia (1), GUILLAUME Olivier (1),
GOUDEMAND Ellen (2), ROBERT Olivier (2), DUCHALAIS Laure (3), TABIB
GHAFFARY Seyed Mahmod (4), KEMA Gert (4)
(1) Arvalis Institut-du-végétal, Paris, France (2) Florimond-Desprez, Cappelle en Pevele, France (3)
RAGT 2n, Louville La Chenard, France (4) PRI, Wageningen University, Wageningen, The Netherlands
Genetic architecture of Septoria tritici blotch resistance in French elite winter
wheats
Septoria tritici blotch (STB) caused by Zymoseptoria tritici is the most damaging disease in
Western Europe. To date, 21 major resistance genes have been identified since the 2000s.
None of them have been cloned and the majority of linked markers published are not
sufficient to follow the genes. Few of them seem present in French cultivated lines. In order
to understand resistance in cultivated elite lines, 146 cultivated lines and 60 breeding lines
have been tested in 4 locations at adult and young stage, after inoculation with 2 different
isolates. Level of disease, fungi biomass quantity and yield components were evaluated.
Association mapping analysis was carried out with circa 150,000 SNP (part from the TaBW420K
affymetrix chip), 400 SSRs and 1500 Darts. A total of 33 QTLs linked to disease traits were
detected at both stages. None were isolate-specific, but the virulences of the 2 isolates are
not very contrasted. Analysis of co-localisation between these QTLs and known Stb genes or
other QTLs detected in similar published studies allow us to show that there is no concordance
with Stb genes except with Stb15 on 6A, confirming the small impact and use of Stb genes in
French elite wheats. We also highlight that 6 QTLs were already detected in breeding
populations from french and exotic lines crosses analyzed a few years ago. A prediction model
based on these QTLs was constructed in order to attempt identifying resistant and susceptible
lines. This work is a good illustration of the complexity of the genetic architecture involved in
the resistance to septoria. Existing French elite material can probably be recombined to
improve resistance via small increments, using whole genome genomic prediction. Marker
assisted selection for known Stb genes has not been advanced by this work because these
genes are probably too rare in French elite material. Mobilizing these resistance genes and
new ones via marker assisted selection would require finer mapping in specific populations.
SPEAKER ABSTRACTS
Saturday 9 April
15:20 - 15:350
MACCAFERRI Marco (1)
AOUINI Lamia (2), PRODI Antonio (1), STEFANELLI Sandra (1), CORNETI Simona
(1), TUBEROSA Roberto (1), MANTOVANI Paola (3), MASSI Andrea (1), KEMA Gert
HJ (2)
(1) Department of Agricultural Sciences (DipSA), University of Bologna, Bologna, Italy (2) Wageningen
University and Research Center, Plant Research International, Wageningen, The Netherlands (3)
Società Produttori Sementi Spa, Argelato, Italy
QTLs for partial resistance to Zymoseptoria tritici in durum wheat
recombinant inbred line populations
Septoria tritici blotch (STB), caused by Zymoseptoria tritici, is a major problem for durum
wheat production, particularly in the Mediterranean region. This notwithstanding, no QTL has
so far been described in the cultivated durum wheat germplasm that can be readily used in
breeding and marker-assisted selection. We developed two recombinant inbred line (RIL)
populations from modern Italian and US durum wheat cultivars, viz. Kofa/Svevo [KS] and
Simeto/Levante [SL] with 249 and 180 RILs, respectively. These populations were evaluated
for STB resistance at the seedling stage (greenhouse) and adult plant stage (field), using
defined Mediterranean and European Z. tritici isolates. Two dense linkage maps, including 243
SSRs, 307 DArT markers and 5,315 Illumina transcript-derived SNPs, were constructed. Four
QTLs on chromosomes 1B, 3B, 4A and 4B provided partial resistance to Z. tritici under field
conditions (R2 values from 5 to 15%) were identified in KS. Additionally, one major QTL located
on chromosome 6B was effective in SL, with R2 value close to 17%. These QTLs have been
identified for STB infection severity at the adult plant stage, i.e. on the flag leaf canopy area,
a stage where STB can compromise yield, grain weight and quality of durum wheat production.
Notably, the QTLs on chromosomes 4B and 6B are novel as compared to those described in
bread wheat and the moderately resistant cv. Svevo carries the alleles conferring partial STB
resistance at the three QTLs on chromosomes 1B, 4A and 4B. The QTLs on chromosomes 6B
and 4B resulted on SL were also effective at the seedling stage and conferred major and minor
effects at 19 dpi, respectively. In addition, we mapped QTLs on SL chromosomes 3A and 7A,
which were only expressed in the seedling stage and had major and minor effects at 21 dpi,
respectively. QTL analyses for KS seedling data are underway. Overall, the identified QTLs are
of great interest for breeding activities aimed at enhancing STB resistance in elite durum
wheat germplasm.
SPEAKER ABSTRACTS
Saturday 9 April
15:35 - 15:50
AOUINI Lamia (1)
FARIS Justin (2), HAMZA Sonia (3), KEMA Gert H.J (1)
(1) Wageningen University., Wageningen, The Netherlands (2) Department of Agriculture, USDA,
Fargo, USA (3) INAT, Tunis, Tunisia
Novel and broad-spectrum resistance to Zymoseptoria tritici in durum wheat
Virtually all studies of resistance to the foliar blight pathogen Zymoseptoria tritici have focused
on bread wheat and have resulted in the identification of 21 Stb genes. In contrast, not a single
gene for resistance has been mapped in durum wheat. Here, we address this lack of
information and report the discovery of a range of QTLs providing complete resistance to Z.
tritici in various landraces and cultivated emmer wheat (Triticum dicoccum). Interestingly, the
landraces and emmer wheat accessions showed a broad efficacy of resistance to a large
number of Z. tritici isolates. Analyses revealed a QTL with major effects on chromosome arm
3AL in T. dicoccum, thereby representing a new and unique genomic position for resistance
breeding in durum wheat against Z. tritici. In addition, we identified two additional QTLs in
segregating populations derived from the Tunisian landrace Agili 39 at the seedling stage. A
major QTL for overall resistance was identified on chromosome arm 2BL. This QTL was
effective against multiple durum derived Z. tritici isolates from various origin. Remarkably, this
QTL was closely linked to the Stb9 gene, which was reported in the French cv. Courtot and is
largely ineffective in bread wheat. An additional QTL for seedling resistance for specific
isolates was identified on chromosome 1A, which also represents a new locus. Overall, this
program resulted in the sought-after new leads for resistance breeding to Z. tritici in durum
wheat.
POSTER
ABSTRACTS
POSTER SESSION ABSTRACTS
THU-1
BENTATA Fatiha (1), LABHILILI Mustapha (1), EL AISSAMI Aicha (2), MAAFA Ilyas
(2), IBIJBIJEN Jamal (3), BENTOURTOU Fayçal (3), BENCHACHO Mohamed (4),
ESSAOUADI Naima (4)
(1) National Institute of Agronomical Research , Rabat, Morocco (2) University Mohamed v, Rabat,
Morocco (3) University Moulay Ismail, Meknès, Morocco (4) University Ibn tofail, Kénitra, Morocco
Status of Septoria disease of wheat in Morocco
The Septoria leaf spot of wheat due to Zymoseptoria tritici is now the main disease
encountered in many parts of wheat production in Morocco. It causes significant loss of yield
ranging from 30 to 50%. The aim of this work is to describe the status of this disease of wheat
in Morocco represented by different agro-climatic regions during 2014. To do this, surveys
have been conducted based on the typical symptoms of the disease and by reporting the
prevalence, incidence and severity of attack. The presence of Septoria disease has overtaken
the other foliar diseases such as leaf rust and yellow rust. Note that since the 2008/2009,
Septoria Leaf spot has become more important on durum wheat (Bentata & al., 2014). So on
160 fields visited, represented by 98 for bread wheat and by 60 for durum wheat, we noted
that severity varied from trace levels to 90% and the maximum incidence has reached 100%
on bread wheat as well as for durum in all areas. Fields with traces of the disease were often
those that had received preventive treatment, while those whose treatment was delayed or
did not occur, the impact reached 100%. In fact, Septoria has became a regular problem in our
country.
THU-2
CONFAIS Johann (1), DUCASSE Aurelie (1), GENISSEL Anne (1), GOUT Lilian (2)
(1) BIOGER, INRA, AgroParisTech, Thiverval grignon, France (2) BIOGER, AgroParisTech, , INRA,
Thiverval grignon, France
Resolution of population structure in the wheat pathogen Zymoseptoria tritici
using either 12 or 4000 microsatellite markers
Zymoseptoria tritici (Zt) causes Septoria leaf blotch, one of the most important worldwide
diseases of wheat. Yield losses can reach 50% in disease-conducive climates and epidemics
occur regularly on bread wheat (Triticum aestivum). A set of 614 Z. tritici isolates was sampled
from naturally infected fields of different French regions during two years, and genotyped
using 12 microsatellite markers. The data were analyzed with population genetic statistics and
population structure analyses. The genetic structure of Z. tritici in France is characterized by a
high genetic diversity (95% of unique genotypes), regular recombination (all populations were
in gametic equilibrium), and large gene flow. No significant genetic differentiation was found
among the sampled Z. tritici geographic populations (North and Centre to South-West of
Frence). To further investigate the extent of genetic structure in Z. tritici, we re-sequenced
using Illumina technology the whole genome of 30 isolates from two geographically distant
populations (sampled in the North and the South-West regions of France). The NGS data were
used to identify more than 4000 microsatellite markers and to analyze their variation across
the 30 isolates. In this study, we compared the resolution of these new markers spread across
the genome with the 12 microsatellites previously used in detecting genetic patterns in Z.
tritici.
THU-3
MEAMICHE NEDDAF Hayet (1), AOUINI Lamia (2), BOUZNAD Zouaoui (3), KEMA
Gert (2)
(1) INRAA, Division de Biotechnologies et d’Amélioration des Plantes, Algiers, Algeria (2) Plant Research
International, Wageningen University , Wageningen, The Netherlands (3) ENSA, Département de
Botanique, Laboratoire de Phytopathologie et Biologie Moléculaire, Algiers, Algeria
Zymoseptoria tritici mating type distribution and teleomorph occurence in
wheat fields in Algeria
Septoria Leaf Blotch caused by Zymoseptoria tritici is a major wheat disease worldwide. A set
of 213 isolates of Z. tritici from six locations in North Algeria were analysed with multiplex PCR
to assess the distribution of mating type idiomorphs at different spatial scales. An equal
mating type distribution at all levels studied (lesion, leaf, field and location) indicates that the
Algerian Z. tritici population undergoes frequent sexual reproduction. Results led us to
investigate the presence of the Z. tritici teleomorph in fields with volunteer plants and
stubbles from summer to winter 2015. Microscopic observations allowed the identification of
mature pseudothecia with asci containing eight two-celled ascospores similar to Z. tritici.
Isolation and laboratory trials confirmed that pseudothecia from Z. tritici have been observed
for the first time in Algerian wheat fields.
THU-4
PALICOVÁ Jana (1), HANZALOVÁ Alena (1), ŠÍP Václav (1), CHRPOVÁ Jana (1)
(1) Crop Research Institute, Prague, Czech Republic
Wheat leaf spot diseases in the Czech Republic in the last 16 years
The most important wheat leaf spot pathogens are Zymoseptoria tritici (syn. Mycosphaerella
graminicola) and Parastagonospora nodorum (syn. Phaeosphaeria nodorum ) Pyrenophora
tritici-repentis ( (syn. Drechslera tritici-repentis). The occurrence of these fungi has been
regularly monitored at the Crop Research Institute in Prague since the year 2000. Wheat leaf
samples were collected from different regions of the Czech Republic. Z. tritici was the most
prevalent wheat leaf spot pathogen in the Czech Republic during the observed period. Only in
2000, 2003, 2004, 2011 P. tritici-repentis was the dominant pathogen. P. nodorum was the
most important wheat leaf spot pathogen in the Czech Republic about 40 years ago, but
nowadays it is the least frequent fungus. On the other hand P. nodorum was detected in
almost 40 % of wheat leaf samples in 2014. The spectrum of wheat leaf spot pathogens
occurring in the Czech Republic is very similar to the main wheat foliar pathogens in other
European countries. Five winter wheat cultivars, differing in resistance to Septoria tritici blotch
(STB), were inoculated under field conditions with nine Z. tritici isolates that were obtained
from different regions of the Czech Republic. This study compared isolates, host cultivars and
environmental effects on five traits indicative of STB severity and analysed pathogen
aggressiveness and host-pathogen relations to improve evaluation of cultivar resistance. It
was concluded that investigation into stability of STB resistance across a wide range of
environments is more valuable for breeding purposes than the study of cultivar response to
different isolates. The collection of 193 P. tritici-repentis isolates from the Czech Republic was
separated into 8 races, which are grouped according to their virulence/avirulence
combination to cultivars/lines used as a differential set. Races 1, 2, 3, 4, 6 and 8 were detected
in the Czech Republic. In total, race 1 was dominant (46%), only in the years 2011-2012 race 8
was dominant.
THU-5
WELCH Thomas (1), KILDEA Stephen (2), FEECHAN Angela (1), MCCABE Tom (1)
(1) University College Dublin, Dublin, Ireland (2) Teagasc, The Irish Agriculture and Food Development
Authority, Carlow, IRELAND (3) Department of Agriculture, Food, and Marine, Dublin, Ireland
Adaptation of Irish Zymoseptoria tritici populations to varietal resistances
Septoria tritici blotch is the most important fungal disease of wheat, causing significant crop
losses throughout Europe. In agricultural pathosystems resistant cultivars are typically only
temporarily effective, as widespread growth of said cultivars drives host selection leading to
adaptation. A gene-for-gene interaction between Z. tritici and wheat has been demonstrated
for one cultivar. However other studies have struggled to find cultivar specific adaptation in
other Z. tritici populations. According to neutral genetic theory, if host adaptation at the
cultivar level is occurring we should see reduced genetic variation, and differentiation
between populations from different cultivars. We used microsatellite markers to genotype >
250 Irish isolates of taken from two naturally infected randomized block trials of four different
wheat cultivars, representing a spectrum of resistance to Z. tritici from susceptible to resistant.
By calculating genetic parameters such as overall heterozygosity and fixation index, we aimed
to determine if genetic drift or host selection is impacting genetic structure of the Irish Z. tritici
population. Our results indicate that diversity is distributed almost entirely within rather than
among Irish populations, with little or no differentiation, and very few clone isolates were
found. This confirms that the forces of genetic drift and selection are minor compared to
sexual reproduction, in concurrence with previous Z. tritici population studies.
THU-6
BEL HADJ CHEDLI Rim (1), AKROUTI Waad (1), YAHYAOUI Amor (2), REZGUI Salah
(1)
(1) National Institute of Agronomy of Tunis (INAT), Tunis, Tunisia (2) International Research Center for
Maize and Wheat Improvement, Mexico, Mexico
Incidence evaluation of Zymoseptoria tritici in treated and untreated durum
wheat fields in Northern Tunisia
The degree of host specificity in the Zymoseptoria tritici-wheat pathosystem that has long
been debated. The septoria population in Tunisia is highly variable not only on durum wheat,
but also as has been recently observed on bread wheat and triticale. The objective of this
research was to assess the incidence of Zymoseptoria tritici on farmers’ fields of durum wheat
between treated and untreated fields. Our data is based on a survey of 25 non-irrigated
durum wheat fields located in the sub-humid and semi-arid regions of Northern Tunisia
(Bizerte, Beja, Jendouba and Mannouba). The results suggest that fields located at low altitude
are the most attacked due to dew accumulation for longer periods. Lower winter
temperatures appeared to stimulate disease spread. 45% of the fields surveyed were treated
with a fungicide. Surveyed fields 3, 12, 13, 16, 17 20, 22, 23 and 25 showed higher incidence.
Analysis of variance of the incidence showed a highly significant difference between the
different treatments. 16 fields among the 25 assessed have presented attack percentages
above 40%. This confirms the susceptibility of cultivated wheats used by farmers in Tunisia
and the high virulence of Zymoseptoria tritici populations. The low level of severity noted in
field 2 demonstrates the effectiveness of fungicides. We hypothesize that fungal strains have
not yet acquired fungicide resistance; however fields 22 and 23 showed 62% and 79% higher
incidence even though they were treated. This leads to speculate an ineffective application of
fungicides or a Zymoseptoria population that had acquired resistance to fungicides.
THU-7
BENSLIMANE Hamida (1), YAHYAOUI Amor (2), OURADI Hamida (1),
BENBELKACEM Abdelkader (3), BOUZNED Zouaoui (1), BAUM Micheal (4)
(1) ENSA, Département de Botanique, Algiers, Algeria (2) CYMMIT, Mexico city, Mexico (3) INRA, Unité
de Recherche de Constantine, Constantine, Algeria (4) ICARDA, Aman , Jordan
Current knowledge of tan spot in North Africa and Middle East
Tan spot, caused by Pyrenophora tritici-repentis, has been a serious disease of wheat in North
African and the Middle East for a long time. These areas have a special interest because they
are close to the wheat origin centre. A collection of isolates sampled from several wheat
growing areas in Algeria and Syria as models for North Africa and Middle East respectively,
have been studied. Isolates from Algeria showed a wide morphologically variation. When 55
isolates from 15 departments were studied using a differential bread and durum host set,
races 1, 4, 5, 6, 7 and 8 were found and a new virulence pattern was identified. Amplification
of ToxA and ToxB virulence genes showed that the genome of isolates sampled from Algeria
and Syria harboured both genes. Otherwise, fluorescent Amplified Fragment Length
Polymorphism (AFLP), revealed high genetic diversity in both Algerian and Syrian populations.
Analysis of the molecular data showed that clustering of the isolates was independent of their
race classification, geographic origin, or host plant. However, one isolate from Algeria that
showed a new virulence pattern was clearly distinguished from the rest of the population
studied. Using resistant varieties is still the best way to overcome this disease, even though
until now no resistant sources were found in Syria while a few varieties of durum wheat
showed an appreciable level of resistance in Algeria. The current knowledge about the causal
agent of tan spot in these two areas displayed the high variability of the pathogen.
THU-8
BOIXEL Anne-Lise (1), VIDAL Tiphaine (1), LUSLEY Pauline (1), DURAND Brigitte
(1), LECONTE Marc (2), DE VALLAVIEILLE-POPE Claude (2), HUBER Laurent (1),
SAINT-JEAN Sébastien (1)
(1) ECOSYS AgroParisTech, INRA, Thiverval-Grignon, France (2) BIOGER AgroParisTech, INRA, ThivervalGrignon, France
Mixing wheat varieties with contrasted architecture to reduce Septoria tritici
blotch splash-dispersed epidemics
Mixing varieties with different levels of disease resistance provide a way to limit the
progression of polycyclic epidemics. In such mixture configurations, susceptible varieties are
protected by the presence of more resistant ones through two main mechanisms: barrier and
dilution effects within the mixture. However, the effectiveness of these mixtures in terms of
disease reduction can vary widely depending on the pathosystem, the dispersion mechanism
and climatic conditions. Such variability has notably been pointed out in the case of the rainsplash dispersed disease, Septoria tritici blotch (STB, caused by Zymoseptoria tritici).
Considering the impact of crop architecture on epidemic development within pure stands, the
architectural lever, which consists of mixing plants, which differ in their architectural
properties, appears as a candidate to improve mixture efficiency to control epidemics. The
work presented here aimed at assessing if contrasted architecture between varieties could be
an additional lever to design cultivar mixtures in addition to resistance. To this end, we
conducted a micro-plot field trial in which we studied mixtures of cultivars with contrasted
resistance to STB and either similar or contrasted architecture (difference in straw height).
These cultivars were also grown in pure stands as a reference. Pathogen vertical dispersal
gradients, STB severity at leaf scale, crop architecture and microclimatic conditions were
monitored and compared between the different types of mixtures and pure stands during an
annual epidemic. We highlighted the relative protection of susceptible short-strawed wheat
in mixture with partially resistant tall-strawed wheat compared to the pure stand and the
mixture with partially resistant short-strawed wheat. Mixed with a partially resistant tallstrawed wheat, severity of the three upper leaves of the susceptible cultivar was reduced by
53% compared to the conventional mixture and by 68% compared to the pure stand. The
number of new lesions on the susceptible component was also reduced in mixtures with
contrasted architecture of their components partly due to a stronger umbrella effect
(raindrops interception by resistant leaves). This study outlines that mixtures efficiency to
control STB progress can be improved by combining components of contrasted architecture
in the design of cultivar mixtures in addition to resistance.
THU-9
BOUKEF Sameh (1),BEN M'BAREK Sarrah (2), YAHYAOUI Amor (3)
(1) High Agronomic Institute of Chott Mariem, Sousse, Tunisia (2) Laboratory of Molecular Plant
Physiology Biotechnology Center of Borj Cedria, Tunis, Tunisia (3) CIMMYT, Mexico-El Batan, Mexico
Preliminary identification and characterization of Zymoseptoria spp. on wild
grasses and spontaneous herbaceous species in wheat fields in Tunisia
The genus Zymoseptoria includes the prominent wheat pathogen Zymoseptoria tritici
(teleomorph Mycosphaerella graminicola) that causes Septoria tritici blotch disease in wheat
worldwide. In Tunisia, Z. tritici is considered as a severe disease of durum wheat cultivars;
lower severity disease is recorded on bread wheat and triticale. Several species showing
septoria-like leaf symptoms were found on a variety of wild grasses (Avena fatua, Bromus
arvensis, Phalaris sp., Lolium sp.) and herbaceous species such as Gladiolus italicus,
Convolvulus arvensis and Lepidium sp. surrounding wheat. Septoria-like species were collected
from several locations in the north of Tunisia during 2014-2015. The primary focus of this work
is to describe the Zymoseptoria species in Tunisia by means of morphological characteristics
and phylogenetic analyses. In addition, we will also test the host specialization of
Zymoseptoria species including Z. tritici either on cultivated wheat and triticale or
spontaneous hosts. These data will be used to evaluate the role of these spontaneous plants
as alternative host for Z. tritici during field epidemic but also during the inter-epidemic period.
Finally, these species will be tested as potential biological control agents for invasive weedy
species for wheat crop in Tunisia.
THU-10
COLLIN François (1), GOUACHE David (2), BANCAL Marie-Odile (3), BANCAL
Pierre (1)
(1) ECOSYS, INRA, AgroParisTech, Thiverval-Grignon, France (2) Arvalis, Institut du Végétal, Boigneville,
France (3) ECOSYS, AgroParisTech, INRA, Thiverval-Grignon, France
Tolerance of wheat to Septoria tritici blotch; genetic vs environmental
variations of key traits
In crop science, tolerance is the ability of a crop to maintain yield performance in the presence
of expressed symptoms. Septoria tritici blotch (STB) is a major bread wheat (Triticum aestivum
L.) pathogen attacking the leaves and reducing the photosynthetically active area; STB reduces
the photosynthesis of the crop and so the yield. Genotypic trait combinations can enhance
tolerance potential to disease. On historical datasets, Bancal et al. (2015) showed that the
curvilinear relationship between yield and Green Leaf Area Duration (GLAD), results in an
increased potential for tolerance of high-GLAD crops. GLAD source variability is composed of
Leaf Area Index (LAI) and senescence kinetics. High LAI increases GLAD but also potential for
high disease pressure, wether late senescence increases GLAD and tolerance. Some sink and
sink-to-source traits characterizing grain filling are also involved in tolerance. These traits are
influenced by the genotype and the environment. Knowledge of the variability of each trait is
needed to understand and combine the levers that control their expression and therefore to
promote tolerance. This preliminary step is of interest to prioritise the treatments to apply to
enhance contrasted senescence patterns and grain filling strategies in further experiments in
controlled conditions.
THU-11
DELLER Siân (1), CARTER Helen (1), CLAKE Helen (1), SCOTT Eileen (1), CSUKAI
Michael (1)
(1) Syngenta, Jealott’s Hill IRC, Bracknell, Berks, UK
Fungicide invention: Fungal genetics tools and challenges in Zymoseptoria
tritici
Chemical control agents are likely to remain a part of the mixture of control strategies open
to farmers for the foreseeable future. In order to support the discovery and development of
new active ingredients a wide range of chemical genetic tools are utilised and are under
constant development. Historically many of these tools used the model organism
Saccharomyces cerevisiae, but improvements in genomic information and tools make it
possible to perform research directly in field-relevant plant pathogens. Some of the wide
range of tools used in support of new fungicide discovery will be outlined, including: Forward
genetic tools, which have long been the mainstay of mode of action diagnosis, provide an
unbiased approach for the identification of the molecular target of a chemical inhibitor. If
resistant mutants can be generated, the technique can now be applied to any pathogen,
providing a reference genome is available and single nucleus cells/spores can be isolated.
Chemistry with lower resistance risk is often associated with the inability to isolate resistant
mutants in the plant pathogen of interest. In this case unbiased genetic tools are still of value
and model organisms are employed. Haploinsufficiency or overexpression-induced resistance
within a yeast library can provide information on proteins or protein families targeted by novel
chemistry. Hypotheses can then be based on the mutations seen, and compared to
information from additional phenotypes such as biochemical pathway inhibition and
microscopic observations. The improvements in transformation procedures, genetic
engineering techniques and availability of multiple selectable markers make it possible to test
hypotheses in fungal pathogens of economic importance such as Zymoseptoria. Additionally,
genes from any species can be tested in a uniform host cell background, for instance, by
heterologous expression. Furthermore, these tools can be used to assess the lifetime of a new
fungicide product. Mutations induced in the lab or discovered in the field can be assessed for
their importance in different genetic backgrounds and an assessment made of the impact on
sensitivity and fitness. Examples of how these tools have been used to study Zymoseptoria
will be shown.
THU-12
DUVIVIER Maxime (1), DEDEURWAERDER Géraldine (2), DE PROFT Michel (1),
LEGRÈVE Anne (2)
(1) Walloon Agricultural Research Center, Plant Protection and Ecotoxicology Unit, Gembloux,
BELGIUM (2) Université Catholique de Louvain, Earth and Life Institute, Louvain-la-Neuve, Belgium
A mechanistic approach for assessing the role of splashborne vs airborne
inoculum in Septoria tritici blotch infections of the upper leaves of wheat
The vertical dispersal of Zymoseptoria tritici (syn. Septoria tritici) on wheat plants can be
achieved by splashborne pycnidiospores or airborne ascospores. A third possible dispersal
mechanism is the overlapping between a Septoria tritici blotch (STB) infected leaf and an
emerging one, leading to a transfer of pycnidiospores without the need for high-energy
droplets. In the present study, a mechanistic approach was used to assess the importance of
the three dispersal mechanisms in the epidemiology of STB. A network of four Burkard 7-day
volumetric spore traps, set up in trial fields in Belgium, operated continuously between March
and June over five growing seasons (2009-2013) with the aim of trapping airborne STB
inoculum above the canopy. The phenology of plants in each field, STB disease severity and
climatic conditions were also assessed over these seasons. The STB airborne inoculum was
quantified using a quantitative PCR assay. In 83.5 % of the cases, airborne STB inoculum was
detected between the emergence of the three last leaf layers in the wheat plants and the end
of their calculated period of infection, with the inoculum load sometimes exceeding 1 400
cDNA/m³ air. In an attempt to quantify the relative importance of each dispersal mechanism
in the initial contamination observed on the upper leaf layers, three models - one model for
each dispersal mechanism - were developed using a mechanistic approach based on
knowledge of STB epidemiology and the data collected over the five growing seasons. When
each dispersal mechanism was considered separately, the best fitted models, obtained by
maximizing the probability of detection and keeping the false alarm ratio below 30%, could
partly explain the contamination of the three upper leaf layers: 50-58% by splashborne
dispersal of pycnidiospores, 42-46% by airborne dispersal of ascospores and 11-12% by
dispersal of pycnidiospores by leaf overlapping. When the three models were combined, the
compilation model could explain up to 68-78% of the contaminations observed in the fields.
The compilation model was then used to explain first contamination observed on flag leaves
of plants treated with fungicides at GS32. This model was particularly well suited in this case,
explaining 92-96% of the contaminations observed. Our mechanistic approach suggests that
airborne STB particles could possibly play an important role in the primary contamination of
the upper leaves of wheat particularly when upward dispersal by asexual spores is slowed
down (e.g., by early fungicide treatment or the use of a resistant cultivar).
THU-13
FEODOROVA-FEDOTOVA Liga (1), VIGULE Zane (1), TREIKALE Olga (1)
(1) Latvian Plant Protection Research Centre Ltd., Riga, Latvia
Interaction between the severity of Zymoseptoria tritici and yield losses in
winter wheat in Latvia
Winter wheat is the most cultivated field crop in Latvia; sowing area in 2010-2014 reached
25.0 MHa; 44.9% of the total field crop sowing area. One of the most harmful diseases in
winter wheat is speckled leaf blotch caused by Zymoseptoria tritici (Desm.) Quaedvlieg &
Crous 2011 (also known as Mycosphaerella graminicola and Septoria tritici). It has a negative
impact on yield. Fungicide applications play important role in managing the speckled leaf
blotch. At the same time it is of concern that resistance to QoI fungicides (strobilurins) appears
to be present in the pathogen population. QoI resistance has been verified in Nordic/Baltic
region, including Latvia (2002). Data of field trials carried out at the Latvian Plant protection
research centre showed that under agrometeorological conditions of last three years severity
of Zymoseptoria tritici varied from 0.4 to 11.4% in 2013, from 1.0 to 22.5% in 2014 and from
0.4 up to 25.9%.The data from field trials showed the losses of the grain yield depending on
severity of speckled leaf blotch by leaf layer in winter wheat cultivars Skagen and Zentos. A
high influence on grain yield losses in untreated was approved by development of Z. tritici on
flag leaf at BBCH 73-75 in winter wheat (cv. Zentos y=-0.052x + 8.586; r=-0.842; cv. Skagen y=0.379x + 7.881; r=-0.829), on second leaf at BBCH 61-65 (cv. Zentos y=- 0.087x + 8.579; r=0.872; cv. Skagen y=-0.136x + 7.866; r=-0.791).
THU-14
HASSINE Marwa (1), BARAKET Mokhtar (2), GUESMI Mouna (2), HAMADA
Walid (1), REZGUI Salah (1)
(1) National Institute of Agriculture of Tunis, Tunis, TUNISIA (2) Regional Field Crops Research Center
Beja-Tunisia , Beja, Tunisia
Assessment of Septoria effects on durum wheat cultivars using stimulators of
natural defence (SND) in north-west Tunisia
Four durum wheat (Triticum turgidum var. durum L.) cultivars with various susceptibility level
were assessed for possible response to Zymoseptoria tritici using two Stimulators of Natural
Defence (SND) derived from algal extracts and a polysaccharide provided by the department
of agronomy and plant biotechnology of the National Institute of Agriculture of Tunis. The test
was done at two locations in North Western Tunisia representing sub-humid (Beja) and semiarid (Oued Mliz) climatic conditions. The varieties assessed were commercially grown
cultivars ; susceptible (Karim) and resistant (Salim). Disease severity was assessed using
double digit scale and thousand kernel weights were measured. Preliminary results showed
that the resistant cultivar Salim had 6% yield advantage over the susceptible cultivar (Karim).
The increase in thousand kernel weights associated to the SND treatments varied from 5 to
18% with Salim and Karim, respectively. The SND treatments indicated that the severity to Z.
tritici of resistant (Salim) and susceptible (Karim) cultivars was reduced to 4% and 5% than the
controls. This result suggests that both elicitors tested could perceived as key factors of the
pathogenicity of Zymoseptoria tritici that was found alleviated and may enhance grain yield
on durum wheat.
Session 3: Pathogen Genetics and Genomics
THU-15
HAWKINS Wayne (1), BORGES Leandro (1), DHILLON Braham (1), RAMEGOWDA
Yamunarani (1), RIDENOUR John (1), ZACCARON Marcio (1), RUPE John (1),
BLUHM Burton (1)
(1) University of Arkansas, Fayetteville, USA
HAP3 of Phomopsis longicolla influences growth, development, and
pathogenesis
Phomopsis longicola (Hobbs) causes Phomopsis seed decay, one of the most prevalent and
potentially damaging diseases of soybean seed. Currently, little is known about the molecular
basis of pathogenesis in P. longicolla, in part because crucial tools for molecular genetics, such
as targeted gene deletion, have not been demonstrated in this organism. In other filamentous
fungi, the heterotrimeric CCAAT-binding complex is involved in diverse aspects of growth and
development, including secondary metabolism, morphogenesis, and pathogenesis. In this
study, a putative component of the CCAAT-binding complex (HAP3) was identified in P.
longicolla and characterized through functional genomics. The HAP3 gene was successfully
deleted via homologous recombination, and the mutant was genetically complemented via
reintroduction of the wild-type gene. Deletion of HAP3 substantially impaired radial growth
and induced the formation of rhizomorphic (rope-like) hyphae on defined culture media.
Experiments are being conducted to evaluate the importance of the P. longicolla CCAATbinding complex during pathogenesis. This study demonstrates the feasibility of targeted
gene deletion in P. longicolla and will elucidate the involvement of the CCAAT-binding complex
during the initiation and development of Phomopsis seed decay. Phenotypic similarities
between HAP3 deletion mutants of P. longicolla and other plant pathogenic fungi potentially
indicate broad involvement of the CCAAT-binding complex in plant pathogenesis.
THU-17
KAZEMI Homayoon (1)
(1) Iranian Research Institute of Plant Protection, Tehran, Iran
Study on the efficacy of Flutriafol+Carbendazim SC on septoria leaf blotch of
wheat in Iran
Septoria leaf blotch with causal agent Zymoseptoria tritici is one of the most important disease
of wheat in humid, semi-humid and semi-dry regions of world. In Iran, this disease is
important in Golestan, Khouzestan, Fars, Ilam and other provinces. Chemical control is an
efficient way to reduce the severity of disease and increase the yield. In an experiment
conducted as randomized block design, the efficacy of three fungicides
Flutriafol+Carbendazim (FC) SC at 0.75, 1, 1.25 and 1.5 l/ha, Propiconazole at 1 l/ha and
Tebuconazole at 1 l/ha was studied against septoria leaf blotch of wheat in Khouzestan,
Mazandaran and Ilam provinces. The fungicides were sprayed in one time at the booting stage
and then the disease severity was recorded in plots week-by-week. Disease severity and yield
of treatments, compared to those of the checks. The results indicated that there was
significant difference between treatments based on disease severity and yield. In Mazandaran
province the best results achieved by FC at 1.5 l/ha and in Khouzestan FC at 1.5 and 1.25 l/ha
respectively. In Ilam province, there was no difference between fungicidal treatments.
THU-18
KERDRAON Lydie (1), BALESDENT Marie-Hélène (1), BARRET Matthieu (2),
LAVAL Valérie (1), SUFFERT Frédéric (1)
(1) BIOGER, INRA, AgroParisTech, Thiverval-Grignon, France (2) IRHS, INRA, AgroCampus Ouest,
Université d'Angers, Beaucouzé, France
Microbiome diversity in crop debris and the search for micro-organisms
acting on Zymoseptoria tritici and Leptosphaeria maculans primary inoculum
The contribution of crop debris as inoculum source of many plant pathogens has been
recognized for decades. Two important pathogens in the classical wheat-oilseed rape rotation
are Zymoseptoria tritici (septoria leaf blotch of wheat) and Leptosphaeria maculans (stem
canker of oilseed rape). Both fungi initiate their sexual stages on plant debris during the
intercropping period, which results in ascospore release for subsequent epidemics. Despite
the importance of debris in disease outbreak, few information is known about the structure
and function of microbial communities associated to this plant habitat. The objective of this
work is to characterize bacterial and fungal assemblages associated to wheat and oilseed rape
debris and to assess their relative impacts on the build-up of primary inoculum during the
intercropping period. The challenge is to identify competitive interactions between pathogens
and debris-associated micro-organisms in order to use these latter as potential biocontrol
agents. The study is based on a field design composed of three plots (wheat monoculture,
oilseed rape-wheat rotations) established in the experimental domain of Grignon (Paris basin).
Wheat and oilseed rape crop debris are sampled thrice a year during the ascospore release
period. The structure of debris-associated microbial assemblages is assessed through a
combination of classical microbiological approaches and sequencing of two molecular markers
(16S rRNA gene and ITS1 region of the fungal internal transcribed spacer). Both approaches
will assess the impact of crop sequence on microbial assemblages and should ultimately lead
to the identification of micro-organisms exhibiting antagonistic activities towards either Z.
tritici or L. maculans. To this end, the impact of different microbial assemblages and isolated
species on the ascospore production from wheat debris infected by Z. tritici will be tested in
field and controlled condition experiments.
THU-19
DELGADO Javier (1), KLITTICH Carla (1)
(1) Dow AgroSciences, Indianapolis, USA
Predicting whole-plant control of Zymoseptoria tritici with fungicides on
wheat using in vitro assays
Leaf blotch caused by Zymoseptoria tritici is the most damaging wheat disease in Europe and
commercial wheat production requires foliar application of fungicides. European populations
of Z. tritici historically evolve rapidly and fungicides with novel modes of action are needed.
Most fungicide invention exploits the growth of target fungi in vitro (IV) to screen compounds
for fungitoxicity, but translation of IV toxicity to disease control in a whole plant (WP)
pathosystem can be affected by compound residuality, cuticular penetration, and compound
translocation and redistribution. Curative activity is a desirable fungicide attribute that is
difficult to predict from IV screens. Compounds with curative properties must accumulate
sufficiently in the apoplast to control mycelial growth of the pathogen post-infection. A
comparison between a spore-based Z. tritici IV assay and a mycelial-based IV assay was carried
out to determine if the mycelial assay was a better predictor of curative and protectant WP
disease control. The evaluation of 45 commercial fungicides showed that inhibition of spore
germination was more predictive of WP fungicidal activity than the mycelial IV assay,
predicting both protectant and curative activity. Predictability of the spore-based IV assay was
influenced by mode of action and physical properties of the active ingredients. Furthermore,
the WP protectant assay was a better predictor of curative activity than either of the IV assays.
THU-20
LE MIRE Geraldine (1), SIAH Ali (2), JIJAKLI Haissam (1)
(1) University of Liege, Gembloux Agro Bio Tech, Laboratory of Phytopathology, GEMBLOUX, Belgium
(2) ISA, Pôle Agriculture, BioGAP, Laboratoire Régional de Recherche en Agroalimentaire et
Biotechnologies, Lille, France
New elicitors as biocontrol tools to protect wheat against Septoria Tritici
Blotch
Wheat is one of the most cultivated crops in the European Union. This cereal must however
face important losses every year due to a major foliar disease known as Septoria Tritici Blotch
(STB) caused by the fungus Zymoseptoria tritici. Disease control mainly depends on
phytosanitary products. However, conventional agriculture is evolving towards more
sustainable practices, out of respect for human health and the environment. Elicitors are
considered as promising biological control tools and draw major interest in Integrated Pest
Management strategies. These plant-immunity triggering compounds induce a general
systemic resistance of the plant to a large spectrum of diseases. This study focuses on the
screening of nine potential elicitors to protect winter wheat against Zymoseptoria tritici.
Greenhouse trials were carried out to measure the ability of the different products to reduce
disease foliar symptoms (necrosis, chlorosis and pycnidia). In addition, the biocide activity of
these products towards the pathogen was evaluated under greenhouse and laboratory
conditions. Furthermore, the modes of action of the best elicitors were investigated by
studying the activity of some key defense enzymes of wheat. The corresponding results will
be presented and discussed with the perspective to choose the two best elicitors for field trials
and undertake further investigations on the signaling pathways triggered in the plant.
THU-21
MADARIAGA Ricardo (1), CASTILLO Dalma (1), MATUS Ivan (1), JOBET Claudio
(1), ALFARO Christian (1)
(1) INIA, Fidel Oteiza, Providencia Santiago, Providencia, Chile
Planting date, Triticum phenology and the formation of the teleomorph of
Zymoseptoria tritici on durum and bread wheat in Chile
Septoria Leaf Blotch cause by Zymoseptoria tritici (syn Mycosphaerella graminicola) was
particularly important during crop season 2015-16 in Chile. In order to understand the
absence of Z. tritici sexual stage on living tissues, a serial planting date experiment was
designed. Four Triticum turgidum varieties Llareta, Corcolen, Lleuque and Queule INIA were
planted using a split plot design and four replicates on June, July, August and September 2015.
At the same time, six bread wheats cultivars Pantera, Pandora, Millán, Kipa and the new
Chilean spring wheat varieties Suri and Lasana were planted at the same dates. Six two meters
rows were used on as experimental units. Using the discharge chamber technique, four time
rotation of the lids harboring residues from the planting date experiment on a petri plate
water agar plates it was not possible to detect the presence of the sexual stage on living plants.
However crop residues that were conserved in the field after cereal harvest for a period of
two months after natural decay, start shooting Z. tritici viable virulent ascospores that could
explain the severe incidence on Septoria blotch disease on susceptible cultivars. Additional
results indicate that severity and incidence of STB was remarkably high on bread wheat
cultivars compared to durum wheats that usually are not affected even thought they were
subject to the high disease pressure of the winter months. It is concluded that Chilean durum
wheat germplasm carried significantly high level of resistance to the Septoria leaf blotch
isolates present in the country and that the Z. tritici sexual stage only occur on decomposed
residues from the previous crop season.
THU-22
MATUSINSKY Pavel (1), TVARUZEK Ludvik (1)
(1) Agrotest fyto, Ltd, Kromeriz, Czech Republic
Reaction of important phytopathogenic fungi to fungicides in laboratory
biotests
An agar dilution method was used to determine the inhibitory effect and effective dose (ED50)
of chosen fungicides on the main cereal fungal pathogens. 50 isolates of Microdochium nivale,
41 isolates of Oculimacula spp., 55 isolates of Zymoseptoria tritici, 54 isolates of Pyrenophora
teres and 27 isolates of Ramularia collo-cygni were collected from wheat and barley across
the Czech Republic in 2015. They were tested against active substances from the fungicide
groups QoI-strobilurins (picoxystrobin), SDHI (penthiopyrad) and imidazoles (prochloraz).
47.3% of Z. tritici isolates, showed an increased level of resistance to strobilurins (ED50 > 0.5
µg.ml-1). 100% of Z. tritici isolates were fully sensitive to penthiopyrad (population ED50 = 0.04
µg.ml-1). M. nivale and Oculimacula did not show an increased level of resistance to
prochloraz (populations ED50 = 0.06 and 0.12 µg.ml-1 respectively). 16.6% of isolates P. teres
showed increased level of resistance to strobilurins. 100% of the isolates of P. teres were fully
sensitive to penthiopyrad (population ED50 = 0.05 µg.ml-1). 44% of Ramularia collo-cygni
isolates showed an increased level of resistance to strobilurins. Overall, the most serious
situation is for Z. tritici and R. collo-cygni where the populations showed a significant level of
resistance to strobilurins.
THU-23
MEJRI Samara (1), SIAH Ali (1), COUTTE François (2), TISSERANT Benoit (3),
MAGNIN-ROBERT Maryline (3), RANDOUX Béatrice (3), JACQUES Philippe (4),
KRIER François (2), REIGNAULT Philippe (3), HALAMA Patrice (1)
(1) ICV, Institut Supérieur d’Agriculture, LILLE, France (2) ICV, Université de Lille Sciences et
Technologies, Villeneuve d'Ascq, France (3) UCEIV, Université du Littoral Côte d’Opale, Calais, France
(4) MiPI, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium
Cyclic lipopeptides from Bacillus subtilis protect wheat against Zymoseptoria
tritici
Searching for more environmentally-friendly and less hazardous phytosanitary products such
as bio-fungicides and elicitors for plant protection is currently encouraged, especially in
Europe, where several national action plans aiming at reducing the use of synthetic
conventional fungicides in agriculture were set up. Here, we assessed the efficacy on bread
wheat against Zymoseptoria tritici of three purified cyclic lipopeptides (surfactin, S; fengycin,
F and mycosubtilin, M) produced by the Bacillus subtilis strains BBG125, BBG131 and Bs2504,
respectively, as well as three mixtures of these biomolecules: S+M, F+M and S+F+M. Among
these mixtures, S+M was produced by the B. subtilis strain BBG116. The experiments were
performed in the greenhouse on plants of the susceptible wheat cultivars Dinosor and Alixan,
treated with each biomolecule or combination at 100 mg/L, 52.1 mg/L and 4.2 mg/L two days
before challenge inoculation with the pathogenic Z. tritici strains T01193 and T02596,
respectively. Scoring of disease severity three weeks post-inoculation revealed significant
reductions (up to 70 %) of disease severity and pycnidial density on both cultivars in plants
treated with M, S+M and S+F+M when compared to the non-treated inoculated control. The
highest concentration (100 mg/L) conferred higher protection levels than the intermediate
one (52.1 mg/L), while very low or non-significant protections were obtained with the lowest
concentration (4.2 mg/L). Further investigations revealed that M, S+M and S+F+M inhibited in
vitro fungal growth, with half-maximal inhibitory concentrations of 1.4 mg/L for both M and
S+M and of 4.5 for S+F+M. This study reports for the first time protection efficacy of
lipopeptides from B. subtilis on wheat against Z. tritici. Additional assays will be performed to
determine whether the highlighted efficacy is due only to a direct antifungal effect or also to
an elicitation of plant defense reactions.
THU-24
BATTISTINI Greta (1), CIRIANI Alessandro (1), CAVINA Federico (1), PRODI
Antonio (1), COLLINA Marina (1)
(1) Department of Agricultural Science, University of Bologna, Bologna, Italy
Sensitivity of Italian Zymoseptoria tritici strains to strobilurins: preliminary
results
Septoria leaf bloch (STB) is the most important disease on wheat caused by Zymoseptoria
tritici (syn Mycosphaerella graminicola). The pathogen is particularly widespread in north and
central Europe. In Italy only during the last few years, the incidence of the disease has
increased. Resistant cultivars, cultural management and chemical control are the most
common disease control strategies. The main fungicides used are QoIs, DMIs, and, more
recently, the SDHIs were introduced. The use of the fungicides with a specific mode of action
led to emergence of resistance to QoIs and DMIs in the main wheat cultivation areas in the
word. In Italy no results coming from wide and specific sensitivity monitoring are available,
therefore the aim of the study was to test the sensitivity of Z. tritici strains to QoI in order to
obtain the first data about the Italian scenario. Leaves of bread and durum wheat were
collected during 2015 from 10 fields with different use of fungicides (wild type, experimental
centres and commercial ones) located in the north of Italy. The sensitivity of about 60 isolates
to azoxystrobin at different concentrations (0, 0.001, 0.003, 0.01, 0.03, 0.1, 0.3, 1, 3, 10, 30
mg/L of active ingredient) have been determined in vitro by microtitre assay (Stammler and
Semar, 2011 - Sensitivity of Z. tritici to DMIs across Europe and impact on field performance.
Bulletin OEPP 41:149-155). The EC50 values of the wild types ranged from 0.01 to 0.12 mg/L
of azoxystrobin, while the first analyzed isolates collected from experimental plots and
commercial fields showed EC50s variable from 0.018 to 5.1 mg/L. On the basis of these first
results, we can suppose the presence of a slight decrease of sensitivity of Z. tritici isolates
collected from Italian fields, as defined by Gisi et al. (2005) (in Modern Fungicides and
Antifungal Compounds IV. Dehne, Gisi, Kuck, Russel, Lyr eds., pp 89-101).
THU-25
TONTI Stefano (1), ALVISI Gianpiero (2), CAVINA Federico (1), PECORARO
Francesco (1), PISI Annamaria (1), NIPOTI Paola (1), PRODI Antonio (1)
(1) Department of Agricultural Science, University of Bologna, Bologna, Italy (2) Consorzio dell'Emilia,
Research and Development, Test Facility, San Giorgio di Piano, Bologna, Italy
Zymoseptoria tritici evaluation after a single artificial inoculation at different
vegetative stages of a durum wheat cv. in a Northern Italy region
Septoria tritici blotch (STB) is one of the most damaging disease of wheat caused by
Zymoseptoria tritici (syn Mycosphaerella graminicola and Septoria tritici) and worldwide
spread. SBT is the most important foliar disease of wheat in America, Asia, Northern, Central
Europe and it is a major disease, particularly on durum wheat, in North Africa. In Italy the
average severity of STB infection, detected from 2000 up to 2015 on durum wheat varieties,
has shown an exponential growth trend, that reached its peak between 2007-2010 with a
further peak in 2013 and a slight decline in the last two marketing years. In the plain area
environment of Bologna (Emilia Romagna region, North of Italy) the infection is due to Z. tritici
with yield losses of 30% in years with high inoculum pressure. The aim of this study has been
to evaluate, in the Bologna Plain, in two years’ field trial, the presence of Z. tritici on the flag
leaf in San Carlo, a susceptible Italian durum wheat cultivar, after a single artificial inoculation
at different vegetative stages (BBCH 31, 35, 39, 60) with two different inoculum concentration
(105 and 106 conidia/ml). Visual assessments (Incidence, Disease severity -DS) and DNA
quantification by Real time PCR, using the primer pair ST-rRNA F/R (Guo et al., 2006;
Presymptomatic and quantitative detection of Z. tritici development in wheat using Real Time
PCR. FEMS Microbiol Lett 262:223-229), were set up. The results demonstrate that the BBCH
39 is the most susceptible stage, independently by the concentration of inoculum and climatic
conditions: the year 2012 was characterized by a low infection pressure of the pathogen, while
year 2013 was characterized by a high infection pressure. In the 2013 a good correlation
between DS and DNA quantity was observed. The results obtained point out that the most
suitable period to obtain the best crop protection could be the flag leaf stage, even if Northern
Italian farmers perform the fungicide treatment against STB earlier, at BBCH31 in association
with the herbicide treatment, because cost-effective.
THU-26
SAEED Khaldoon (1) SHAW, Michael (2)
(1) Department of plant protection, University of Tikrit, Tikrit, Iraq. (2) University of Reading, Reading,
UK
Effect of sulphate fertilization on related and absolute abundance of Septoria
pathogens of wheat.
Sulphur pollution is historically correlated to changes in abundance of Zymoseptoria tritici and
Parastagonospora nodorum, and glasshouse experiments suggest this is related to sulphate
nutrition altering the balance of competition between the fungi. Three field experiments were
conducted during 2012-2015, to investigate whether sulphate fertilisation affected Z. tritici
and P. nodorum under UK field conditions. Disease was measured by incidence in 2013, 2014
and 2015, severity in 2013, 2015, leaf wash spore concentration in 2014, 2015 and DNA
concentration in 2014, 2015. The design differed between years in response to results. There
was abundant natural infection by Z. tritici. It was difficult to establish P. nodorum by autumn
spray or seed inoculation. However, a spring spray inoculation was successful in 2015. Z. tritici
leaf incidence, severity and spore concentration were consistently reduced in plots receiving
sulphate. Sulphate fertilization reduced the proportion of Z. tritici infected leaves by 12% and
7.5% at growth stage (GS) 31 and 59 (P = 0.006, P = <0.001) respectively in 2014, and reduced
by 33% and 13% at GS 31, 77 (P = <0.001, P = <0.001) respectively in 2015. Severity was
reduced by 28% at GS 77 (P = 0.011) in 2015, but not significantly reduced in 2013. Spore
concentration was reduced by 54% at GS 59 (P = <0.001) in 2014. In the 2015 experiment it
was reduced by 71% and 56% at GS 31 and 77 (P = <0.001, <0.001) respectively. The
concentration of Z. tritici DNA at GS 59 was reduced by 24 % with sulphate fertilization (P =
0.03) in 2014. In the 2015 experiment the concentration of Z. tritici DNA was reduced by 42%
(P = 0.016) at GS 31 and by 18% at GS 80 (but not significantly, P = 0.3). Sulphate reduced
proportion of leaves with P. nodorum by 26% (P = 0.015) and spore concentration by 33% (P
= 0.049). This suggested a greater effect of sulphate fertilization on Z. tritici than P. nodorum,
which agrees with the historical record.
THU-27
SOMAI Lamia (1), SIAH Ali (2), RANDOUX Beatrice (3), MAGNIN-ROBERT
Maryline (3), HALAMA Patrice (2), REIGNAULT Philippe (3), HAMADA Walid (1)
(1) Laboratoire de Génétique et Amélioration des Plantes, INAT, Tunis, Tunisia (2) Laboratoire
Biotechnologie et Gestion des Agents Pathogènes en agriculture, Institut Charles Viollette, GIS
PhyNoPiISA, Lille, France (3) Université du Littoral Côte d’Opale, UCEI Université Lille-Nord de France,
GIS PhyNoPi, Calais cedex, France
Ascophyllum nodosum extract: enhancer of bread and durum wheat defence
mechanisms against Zymoseptoria tritici
This study aims at characterizing the antifungal and resistance inducer (RI) activities of an
Aschophyllum nodosum extract-based (A. nod) against Zymoseptoria tritici, major cereal
pathogen on both bread (BW) and durum wheat (DW). In in vitro conditions, this extract did
not exhibit any antifungal effect, whereas in greenhouse conditions it could reduce at least 2fold the symptom severity. Concerning fungal development, it strongly decreased Z. tritici cell
wall degrading enzymes activities, such as endo-beta-1,4-xylanase, endo-beta-1,3-glucanase
and protease during the necrotrophic phase associated with reduced fructification.
Concerning plant defense induction, A. nod treatment increased the expression of beta-1,3glucanase (PR2)-, peroxidase (Pox)-, lipoxigenase (LOX)- and phenylalanine ammonia lyase
(PAL) genes and corresponding glucanase, peroxidase, catalase, PAL and LOX activities on both
wheat species. At the cytological level, H2O2 accumulation and polyphenols deposition were
enhanced by the fungal penetration. Therefore, A. nod induced a range of wheat defense
responses such as reactive oxygen species (ROS) metabolism, phenylpropanoid and
octadecanoid pathways. Moreover, BW and DW exhibited distinct response profiles to the A.
nod treatment. ROS metabolism and octadecanoid pathway were more responsive in BW,
while phenylpropanoid pathway was activated to a greater extent in DW. Thus, A. nod confers
a significant protection level to Z. tritici, associated with a set of induced wheat defenses. It
can be used as an alternative to chemical control of Z. tritici on both wheat species.
Nevertheless, there are still gaps to fill in order to elucidate reasons of distinct response of
wheat species to this RI.
THU-28
TRABELSI Imen (1), OTHMENI Manel (1), FAKHFAKH Moez (2), KHAMASSI
Messaad (3), BARAKET Mokhtar (4), YAHYAOUI Amor (5)
(1) INRAT, Tunis, Tunisia (2) Société de Semence (CMA) Tunisie, Tunis, Tunisia (3) INGC, Bousalem,
Tunisia (4) CRRGCB, Beja, Tunisia (5) CIMMYT, Mexico
Preventive control of weeds and Zymoseptoria tritici in durum wheat
Durum wheat is the major cereal crop in Tunisia and occupies over 50% of cultivated areas.
The intensive cropping of durum wheat particularly in Northern Tunisia led to mono-cropping
of a highly productive variety cv. Karim released in Tunisia in 1983. This variety has good yield,
wide adaptation, and good quality; hence its wide adoption by farmers over the last three
decades. The introduction of conservation agriculture practices and the wide areas cultivated
under cv. Karim lead to its high susceptibility to Septoria tritici blotch (STB). During epidemic
years (cool weather and high rainfall) yield losses reach up to 60% while in normal years
(moderate rainfall) losses of 20-30% are common. While attached to the variety Karim,
farmers try to maintain its yield level and avoid high losses; hence they opt for the use of
fungicides where often three applications are needed. Weed control is also another limiting
factor to wheat production; farmers regularly apply herbicides and are often successful in
managing weeds. To reduce pesticide applications costs; we envisage the combined
application of herbicide-fungicide. In areas under zero tillage that harbors inoculum from
previous crop- a potential source of primary inoculum; early application of fungicides could
prevent disease spread.Two commercially registered fungicides (Opus and Sherokee) and
three herbicides (Amilcar, Pallas, and Lancelot) were tested under different combinations.
Primary results show reduction in disease severity and good yield were observed with a
combination of the fungicide Sherokee and the herbicide Amilcar. Better combinations of
targeted fungicides and herbicides could be identified and recommended to farmers in
Zymoseptoria prone areas. Details of our results will be discussed.
THU-30
VIDAL Tiphaine (1), LUSLEY Pauline (1), DURAND Brigitte (1), LECONTE Marc (2),
DE VALLAVIEILLE-POPE Claude (2), HUBER Laurent (1), SAINT-JEAN Sébastien (1)
(1) ECOSYS, AgroParisTech, INRA, Thiverval-Grignon, FRANCE (2) BIOGER, AgroParisTech, INRA,
Thiverval-Grignon, FRANCE
Mixing wheat varieties with contrasted architecture to reduce Septoria tritici
blotch splash dispersed epidemics
Mixing varieties with different levels of disease resistance provides a way to limit the
progression of polycyclic epidemics. In such mixture configurations, susceptible varieties are
protected by the presence of more resistant ones through two main mechanisms: barrier and
dilution effects within the mixture. However, the effectiveness of these mixtures in terms of
disease reduction can vary widely depending on the pathosystem, the dispersal mechanism
and climatic conditions. Such variability has notably been pointed out in the case of the rainsplash dispersed disease: Septoria tritici blotch (STB). Considering the impact of crop
architecture on epidemic development within pure stands, the architectural lever, which
consists of mixing plants, which differ in their architectural properties, appears may a mean
to improve mixture efficiency to control epidemics. The work presented here aimed at
assessing if contrasted architecture between varieties could be an additional lever to design
cultivar mixtures in addition to resistance. To this end, we conducted a micro-plot field trial in
which we studied mixtures of cultivars with contrasted resistance to STB and either similar or
contrasted architecture (difference in straw height). These cultivars were also grown in pure
stands as a reference. Pathogen vertical dispersal gradients, STB severity at leaf scale, crop
architecture and microclimatic conditions were monitored and compared between the
different types of mixtures and pure stands during an annual epidemic. We highlighted the
relative protection of susceptible short-strawed wheat in mixture with partially resistant tallstrawed wheat compared to the pure stand and the mixture with partially resistant shortstrawed wheat. Mixed with a partially resistant tall-strawed wheat, severity of the three upper
leaves of the susceptible cultivar was reduced by 53% compared to the conventional mixture
and by 68% compared to the pure stand. The number of new lesions on the susceptible
component was also reduced in mixtures with contrasted architecture of their components
partly due to a stronger umbrella effect (raindrops interception by resistant leaves). This study
outlines that mixtures efficiency to control STB progress can be improved by combining
components of contrasted architecture in the design of cultivar mixtures in addition to
resistance.
THU-31
WIECZOREK Thies Marten (1), JØRGENSEN Lise Nistrup (1)
(1) Aarhus University, Flakkebjerg, Dept. of Agroecology, Slagelse, Denmark
CYP51 insertions conferring reduced fungicide sensitivity in Z. tritici isolates
from Denmark and Sweden
In the past decade reduced sensitivity of sterol 14-demethylase inhibitors (DMI) in the wheat
pathogen Z. tritici has increased. This decline has been associated with three mechanisms: (1)
point mutations in the target gene 14-demethylase (CYP51), (2) an enhanced efflux (MDR)
and (3) an overexpression of the CYP51 gene. In several plant pathogens, CYP51
overexpression is correlated with changes in the promoter. In Z. tritici two insertions have
been identified in the CYP51 promoter region; 120 bp and 1000 bp, located 200 bp upstream
from the start codon. Whereas it was shown that the 120 bp insert contributes to the decrease
of sensitivity to several DMIs (2), it has not yet been demonstrated that the 1000 bp long insert
might lead to an increase of CYP51 levels. In 2013, a total of 296 isolates from Denmark and
Sweden were tested for the presence of inserts in the CYP51 promoter region. Out of the
tested 226 Danish isolates 46% had the 1000 bp insert. Out of the tested 70 Swedish isolates
64% had the 1000 bp insert. The 120 bp insert occurred in Denmark and Sweden at low levels
of 2 and 3%, respectively. This is the first evidence of 120 bp strains in Northern Europe.
Isolates with the 120 bp insert had 3x higher EC50 values in Danish isolates and 6x higher EC50
values in Swedish isolates for the DMI epoxiconazole compared with isolates that did not have
any changes in the promoter region. EC50 values for isolates having the 1000 bp were also
slightly elevated, indicating a moderate reduction of sensitivity to epoxiconazole. The high
percentage of the 1000 bp insert, especially in the Swedish population, raises the question
whether it is advantageous for Z. tritici strains to bear the 1000 bp insert. This is currently
further investigated.
(1) Cools HJ, Fraaije BA. Pest Management Science 2013;69(2):150-155.
(2) Cools HJ, Bayon C, Atkins S, Lucas JA, Fraaije BA. Pest Management Science
2012;68(7):1034-1040.
(3) Leroux P, Walker AS. Pest Management Science 2011;67(1):44-59.
Session 3: Pathogen Genetics and Genomics
THU-32
CHAUDHARI Yogesh (1), SIDHU Yaadwinder (1), CAIRNS Timothy (1), ATTAH
Vicky (1), THOMAS Graham (1), STUDHOLME David (1), HAYNES Ken (1)
(1) College of Life and Enviornmental Sciences, Biosciences, University of Exeter, Exeter, UK
Zymoseptoria tritici ORFeome project and its utilisation
Zymoseptoria tritici (syn Mycosphaerella graminicola) is a haploid fungal pathogen that causes
Septoria tritici leaf blotch (STB) in wheat (Triticum species). Although the availability of the
complete Z. tritici genome sequence has contributed a major role in understanding various
aspects of this pathogen, a complete picture of Z. tritici pathogenicity is hindered by the lack
of tools for functional genomics. To fill this gap we have constructed the partial Z. tritici (strain
IPO323) ORFeome library using Gateway® recombination cloning technology. We have cloned
3,775 Illumina sequence verified ORF"s into E. coli Gateway® entry vector pDONR 207.
Alongside this community resource, we also have developed a suite of gateway compatible
destination vectors (Sidhu et al., 2015) which enables us to transfer our genes of interest from
entry clones for over-expression and localisation studies. We are also performing large scale
screening of our Z. tritici over-expression libraries in the heterologous system Saccharomyces
cerevisiae.
THU-32-2
KILDEA Steven (1), DOOLEY Hilda (1), SHAW Michael W. (2), MEHENNI-CIZ Jeanne
(1), SPINK John (1)
(1) Department of Crop Science, TEAGASC Crops, Environment and Land Use Programme, Oak Park,
Carlow, Ireland (2) School of Agriculture, Policy and Development, University of Reading, Whiteknights,
Reading, UK
Sensitivity of Irish Zymoseptoria tritici populations to the succinate
dehydrogenase inhibitor fungicides
As part of the deployment of fungicide anti-resistance strategies it is essential to monitor
Zymoseptora tritici populations and alter programmes to reflect changes in sensitivity.
Knowledge of sensitivity levels in unexposed pathogen populations is used to help identify
early shifts in fungicide sensitivity. Baseline studies can also be used to determine levels of
cross-resistance between active ingredients. The succinate dehydrogenase inhibitor group of
fungicides (SDHI) now play a major role in the management of Z. tritici in Ireland, and
elsewhere in Northern Europe. SDHIs have been classed as having a medium risk-ofresistance; managing that risk is critical if we want the SDHIs to continuing being effective. The
sensitivity of early Irish Z. tritici populations to SDHI fungicides (baseline sensitivity) was
measured and the most recent findings from the Teagasc monitoring programme are
presented here.
THU-32-3
MEHRA Lucky (1), COWGER Christina (2), OJIAMBO Peter (1)
(1) North Carolina State University, Raleigh, USA (2) United States Department of AgricultureAgricultural Research Service, Raleigh, USA
Pre-planting and in-season risk assessment of Septoria nodorum blotch in
winter wheat
Septoria nodorum blotch (SNB), caused by Parastagonospora nodorum, is a major disease of wheat.
The performance of multiple regression (MR) and machine learning algorithms (neural network,
categorical and regression tree, and random forest) was examined in predicting the pre-planting risk
of SNB. The models were developed using 431 disease cases collected from 2012 to 2014. Latitude,
longitude, wheat residue, and cultivar resistance were the most important predictors. Results show
that the random forest (RF) algorithm was the most accurate in predicting the SNB risk and it could
useful in assessing the risk assessment of SNB before planting of the crop. Management of SNB during
the season relies on fungicide sprays after flag leaf emergence. Based on the SNB onset-yield
relationship, day of year (doy) 102 was identified as the cutoff of disease onset where 87% of disease
cases had below average yield when onset occurred before doy 102. Binary logistic regression was
used to predict onset as a function of i) cumulative favorable weather until doy 102 and ii) pre-planting
factors. Wheat residue and cumulative favorable weather until last day of March were found to be
significant (P < 0.001) predictors of SNB onset and the model had a correct classification rate of 0.94.
Once validated using independent data, the model could serve as a within-season tool to help growers
with decisions on fungicide application for SNB management.
THU-32-4
REHFUS Alexandra (1), ACHENBACH Janosch (2), STROBEL Dieter (1), BRYSON
Rosie (1), STAMMLER Gerd (1)
(1) BASF SE, Limburgerhof, Germany (2) BASF SE, Ludwigshafen, Germany
Sensitivity of Pyrenophora teres to SDHIs in Europe
One of the most important diseases of barley worldwide is net blotch caused by Pyrenophora teres. In
addition to strobilurins (QoIs) and azoles, succinate dehydrogenase inhibitors (SDHIs) are very effective
fungicides for net blotch control. Recently, isolates with reduced SDHI sensitivity have been found in
the field. The first isolates with a reduced sensitivity to SDHIs registered in barley were found in
Germany in 2012 and carried the H277Y amino acid exchange in the SDH-B subunit. In 2013 and 2014
a significant increase of isolates with reduced SDHI sensitivity was detected mainly in France and
Germany and the range of target site mutations increased. The majority of such isolates contained the
amino acid exchange G79R in the SDH-C subunit. Other substitutions were observed at a lower
frequency. Microtitre tests showed that all SDHIs tested were cross-resistant. Glasshouse tests showed
that all isolates with a reduced SDHI sensitivity were still well controlled by the SDHI fluxapyroxad when
applied preventatively. In contrast to the development of the QoI mutation, G143A, in the cereal
pathogen Zymoseptoria tritici, the number and impact of the sdh mutations is complex and seems to
be a highly dynamic process. Strict resistance management strategies are recommended to maintain
SDHIs as effective tools for net blotch control.
THU-34
CARLSEN Steve (1), NEUPANE Anjan (1), RICHARDS Jonathon (1), XU Steven (2),
FARIS Justin D. (2), BRUEGGEMAN Robert S. (1), FRIESEN Tim (1)
(1) Department of Plant Pathology, North Dakota State University, Fargo, ND, USA (2) USDA-ARS,
Northern Crop Science Lab, Cereal Crops Research Unit, Fargo, ND, USA
A Pyrenophora teres f. maculata mapping population reveals the complexity
of virulence in spot form net blotch
Pyrenophora teres f. maculata is a major pathogen of barley worldwide, however, little is
known about the virulence underlying this disease. Therefore, a mapping population was
developed using a cross between P. teres f. maculata isolates FGOB10Ptm-1 (North Dakota)
and SG1 (Australia) to derive 105 progeny. The population was phenotyped on four barley
lines (Skiff, 81-82/033, TR326, PI 392501) shown to have strong differential reactions to the
parental isolates. The FGOB10Ptm-1 × SG1 population was subsequently genotyped using a
restriction associated DNA-genotype by sequencing (RAD- GBS) approach developed for the
Ion Torrent PGM. A SNP calling pipeline identified a total of 983 informative markers that were
used to develop the first genetic map of P. teres f. maculata. The 983 markers were distributed
across 16 linkage groups generating a map size of 1650 cM. Using phenotypic and genotypic
data, quantitative trait loci (QTL) analysis identified eight genomic regions significantly
associated with P. teres f. maculata virulence. QTL associated with individual barley lines
ranged from two to four, with each line showing a different QTL pattern. Generation of a
reference quality sequence of parental isolate FGOB10Ptm-1 allowed for candidate gene
identification under the eight genomic regions identified in QTL analysis. Based on the current
annotation, the number of predicted small secreted proteins in each QTL region ranged from
five to fourteen. Among the genes encoding predicted small secreted proteins, 14 are within
an 80 kb range of the QTL peaks, making them strong effector candidates. The number of
genomic regions associated with virulence and the QTL pattern across the different barley
lines indicates a high level of complexity in pathogen virulence.
THU-35
HARTMANN Fanny (1), SÁNCHEZ-VALLET Andrea (1), CROLL Daniel (1)
(1) Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
A segregating gene deletion polymorphism is linked to pathogenicity in
populations of the fungal wheat pathogen Zymoseptoria tritici
The fungus Zymoseptoria tritici is the causal agent of Septoria tritici blotch (STB) of wheat
causing major economic losses. However, the genetic architecture of virulence is poorly
understood in natural populations. We performed a genome-wide association study (GWAS)
to identify genetic variation linked to virulence in natural populations. We analysed 106
isolates originating from four geographical locations: Australia, Israel, Switzerland and the
United States. The isolates showed significant variation in pycnidia production, a key indicator
of virulence in Z. tritici, among populations and depending on the identity of the wheat
cultivar. Using Illumina whole-genome sequencing, we genotyped 779,178 high-quality single
nucleotide polymorphisms (SNPs) segregating in multiple populations. GWAS analyses
identified multiple chromosomal regions associated with virulence, showing that virulence is
based on a complex genetic architecture. We found little overlap in associated regions
identified for each cultivar separately, suggesting that many virulence loci may be cultivarspecific. Significant associations localized to genes encoding for proteins of diverse functions,
including transporters, nutrient degradation and general metabolism. The most significantly
associated SNP was in near complete linkage disequilibrium with a deletion polymorphism of
a gene encoding a small secreted protein. The gene is highly transcribed during leaf infection
and belongs to an important class of virulence gene candidates. In order to characterize the
chromosomal region harboring the gene deletion polymorphism, we used Illumina read
coverage. We found high levels of deletion polymorphisms segregating among the
resequenced isolates. The gene was located at the boundary between a transposable
element-rich region showing large-scale deletion polymorphisms within the species and a
conserved, gene-rich region. Isolates lacking the gene showed higher virulence, suggesting
that the gene plays a role in plant defense activation or recognition. The finding that a gene
deletion polymorphism was strongly associated with virulence shows that chromosomal
rearrangements in pathogen populations can be a major driver of virulence evolution.
THU-36
MEHRABI Rahim (1), MIRZADI GOHARI Amir (2), FERREIRA DA SILVA Gilvan (3),
STEINBERG Gero (4), KEMA Gert H.J. (2), DE WIT Pierre J.G.M. (5)
(1) Seed and Plant Improvement Institute, Agricultural Research, Education and Extension Organization
(AREEO), Karaj, Iran (2) PRI Wageningen University, Wageningen, The Netherlands (3) Laboratory of
Molecular Biology, Embrapa Western Amazon, Manaus, Brazil (4) School of Biosciences, University of
Exeter, Exeter, UK (5) Laboratory of Phytopathology, Wageningen University, Wageningen, The
Netherlands
Flexible gateway constructs for functional analyses of genes in Zymoseptoria
tritici
Genetic manipulation of fungi requires quick, low-cost, efficient, high-throughput and
molecular tools. In this paper, we report 22 entry constructs as new molecular tools based on
the Gateway technology facilitating rapid construction of binary vectors that can be used for
functional analysis of genes in fungi. The entry vectors for single, double or triple genedeletion mutants were developed using hygromycin, geneticin and nourseothricin resistance
genes as selection markers. Furthermore, entry vectors containing green fluorescent (GFP) or
red fluorescent (RFP) in combination with hygromycin, geneticin or nourseothricin selection
markers were generated. The latter vectors provide the possibility of gene deletion and
simultaneous labelling of the fungal transformants with GFP or RFP reporter genes. The
applicability of a number of entry vectors was validated in Zymoseptoria tritici, an important
fungal wheat pathogen.
THU-37
ROOHPARVAR Ramin (1), POORANHAJI SHARABIYANI Maryam (2), TORABI
Mohammad (2)
(1) Cereal Pathology Unit, Departmeant of Cereal Resaerch, Seed and Plant Improvement Institute
(SPII), Agricultural Research, Education & Extension Organization (AREEO), Karaj, Iran (2) Department
of Plant Pathology, College of Agricalture, Islamic Azad University, Varamin, Pishva Bramch, Varamin,
Iran
Pathotypic diversity among Iranian populations of Zymoseptoria tritici, the
fungal wheat oathogen of Septoria tritici botch
Resistance to Zymoseptoria tritici, the fungal wheat pathogen of Septoria tritici blotch (STB)
could be an effective and economic method of disease control by providing effective
resistance gene(s) against virulent pathogen populations. Pathotypic analysis of Z. tritici
isolates could lead to identification of the pathogen avirulence on wheat Stb resistance
gene(s) in infected areas. In this study, 19 isolates were purified from wheat infected leaf
samples collected in 3 different locations. Avir/vir pattern of the isolates was identified
following inoculation of their spore suspension on 26 differential wheat cultivars each carrying
one or more Stb resistance gene(s). The fungal pathotypes were differentiated based on their
virulence on cultivars and the related Stb gene/s. Based on the results, 18 Z. tritici pathotypes
were identified out of 19 fungal isolates indicating a high pathotypic diversity among pathogen
populations in Iran. Isolate 92004 was identified as the most aggressive isolate on differential
cultivars with the highest disease severity of 32.06 %, whereas 92026 showed the lowest
disease severity of 6.018 %. All isolates displayed virulence on Stb2 and Stb6 carried by the
wheat cultivar Veranopolis, as well as on Stb13 and Stb14 (Salamouni), while none of the
isolates was virulent on Stb16, as the most effective Stb resistance gene. The results suggest
that breeding for resistance to STB should be continuously carried out for different locations.
FRI-1
SIAH Ali (1), RANDOUX Béatrice (2)
(1) ICV, Institut Supérieur d’Agriculture, Lille Cedex, France (2) UCEIV, Université du Littoral Côte
d’Opale, Calais cedex, France
Genetic diversity and structure of French Zymoseptoria tritici populations at
different scales
Zymoseptoria tritici is the main pathogen on wheat crops in France, causing each year 1.7
Kg/Ha yield loss in average. Disease control relies mainly on the use of fungicides and resistant
cultivars, but the sustainability of these methods is frequently compromised in the field
because of the regular adaptations set up by the fungus, leading to resistance to fungicides
and overcoming of host resistance. Hence, a deeper understanding of Z. tritici genetic features
can offer valuable information to breeders, scientists and private companies to better adapt
dedicated management strategies. We therefore characterized several populations of Z. tritici
(more than 1500 monoconidial isolates), isolated in France over a ten year period (2005-2015)
at different spatial scales (whole country, Nord-Pas de Calais region, field, 30 cm2 square,
plant, leaf and necrotic lesion). Isolate fingerprinting was carried out using polymorphic
microsatellite markers and using mating type-encoding sequences to evaluate the potential
of sexual reproduction. Results revealed high to moderate levels of genetic diversity within all
assessed populations. Nei"s index values (genic diversity) as well as haplotype fraction
(genotypic diversity) were high and similar at the country, regional and field scales, but the
values of these indices progressively decreased from the field to finest scales such as plant,
leaf and lesion. Bayesian and non-Bayesian statistical analyses revealed significant
structuration of the global French population through three distinct genetic clusters, whereas
the Nord-Pas de Calais population could be divided into three sub-clusters, all distributed
according to their geographical location. On the other hand, no genetic structuration was
found at finest scales. Both fungal mating types were equally distributed at the country, NordPas de Calais and field scales and co-occurred at all other investigated scales, even at the lesion
level. This study highlighted a high genetic diversity for Z. tritici in France, likely due to regular
cycles of genetic recombination in the field, as well as a structuration of its populations at the
country and Nord-Pas de Calais scales, testifying its high fitness degree and its strong ability
to adapt to local agro-climatic conditions.
FRI-02
TILEY Anna (1), FOSTER Gary D. (1), BAILEY Andy M. (1)
(1) School of Biological Sciences, University of Bristol, Bristol, UK
Investigating asexual sporulation in Zymoseptoria tritici, a pathogen of wheat
Zymoseptoria tritici is an ascomycete fungus that causes Septoria tritici blotch, a major disease
of wheat. The fungus spreads to new hosts via asexual spores dispersed by rain splash. A
potential way to control Z. tritici is to prevent asexual sporulation by inhibiting development
of the asexual fruiting body and spores. There is currently limited understanding of Z. tritici at
the molecular level, particularly the genetic pathways involved in asexual sporulation. Key
genes already known to be important for asexual sporulation in other model ascomycete fungi
were BLAST searched against the Z. tritici database to find potential homologues, and their
expression assessed. Genes were selected for knock-out analysis, including those most similar
to the Aspergillus nidulans genes abaA, brlA and flbB. Other candidate genes knocked-out
share similarity to those with roles in light signalling, due to the importance of this pathway
for sporulation in other fungi. The parameters needed for reliable sporulation of Z. tritici have
also been investigated using a range of media and illumination conditions. This will help in the
investigation of the knock-out mutants by uncoupling sporulation from other in planta
phenotypes. 8 genes have been disrupted to date, with experiments ongoing. Current results
suggest that perhaps the A. nidulans model of asexual sporulation does not apply to Z. tritici.
The most recent results from these studies will be presented.
FRI-3
AJIGBOYE Olubukola (1), JAYAWEERA Dasuni (1), FOULKES John (1), MURCHIE
Erik (1), RAY Rumiana (1)
(1) Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Leicestershire,
UK
Physiological traits associated with resistance to Zymoseptoria tritici in two
wheat genotypes
Zymoseptoria tritici, the causal agent of Septoria tritici blotch (STB) disease is one of the most
devastating foliar pathogens of wheat. To initiate STB infection, spores of Z. tritici on contact
with a leaf surface produce hyphae, which enter the leaf through the stomata and begin a
period of slow intercellular filamentous biotrophic growth. Susceptibility to infection by the
pathogen is governed partly by a number of physiological features of the host associated with
initial hyphal development and establishment of the pathogen in the host tissues. This study
investigates the interaction between two contrasting wheat genotypes and Z. tritici during
early STB infection. We evaluated physiological leaf traits of two differing wheat genotypes in
resistance to STB associated with photosynthetic efficiency during early infection by Z. tritici.
Whole plant (GS 13) of Cougar (resistant) and Sacramento (susceptible) were inoculated with
a composite of three isolates of Z. tritici or water, and kept in a dark chamber under high
humidity for 72 h. Stomatal density, stomatal length and stomatal width were measured in
the middle part of adaxial and abaxial surfaces by impression method. Fungal structures were
stained and visualized under light microscope. Gas exchange and chlorophyll fluorescence
were measured at time intervals up to 48 h after inoculation in the dark and at 5 days after
inoculation under light. The results showed significant differences between the varieties for
stomatal characteristics (number and size) and hyphal extension on the adaxial leaf surface.
Stomatal number and size, conductance and non-photochemical quenching were
physiological traits associated with resistance responses in one of the wheat genotypes.
FRI-4
BARTOSIAK Slawomir (1), ARSENIUK Edward (1)
(1) Department of Plant Pathology, Plant Breeding and Acclimatization Institute, National Research
Institute, Radzikow, Poland
Monitoring of pathogenic variability in population of necrotrophic fungal
pathogen Parastagonospora nodorum
Parastagonospora nodorum is the cause of leaf spot and glume blotch of wheat and triticale.
The disease is of high economic importance and it is widely spread in many parts of the world
and can lead to significant yield losses of cereals, and especially wheat. The aim of this study
was to assess variability in pathogenicity of the Polish population of P. nodorum isolates
collected from wheat and triticale in different parts of the country. Pathogenicity tests under
controlled environment were conducted. Cereal cultivars were tested in field trials - 10 of
winter and 6 of spring triticale, 10 varieties of winter and 6 of spring wheat. The plots were
inoculated with spore suspension of P. nodorum at a concentration of 5×106 spores·ml-1. Two
weeks after inoculation the disease progress on leaves and glumes was rated at weekly
intervals on 9 digit scale (1 - susceptible, 9 - resistant). The pathogenicity of P. nodorum
isolates from triticale and wheat was also studied at the seedling stage. In this test, the
seedlings were inoculated by spore suspension of P. nodorum. In the controlled environment
proper humidity, temperature and light exposure for the development of the disease. A large
variability in pathogenicity among P. nodorum isolates was proven to occur in the population
of the fungus studied in Poland. The results indicate that isolates were nearly two times more
pathogenic to winter triticale than to winter wheat. Also significant variability in resistance
among wheat and triticale varieties was found under the controlled environment and in field
conditions.
FRI-5
LEE Wing (1)
(1) Plant Biology and Crop Science Department, Rothamsted Research, Harpenden, UK
Identification and analysis of wheat genes involved in susceptibility to
Zymoseptoria tritici using virus-induced gene silencing (VIGS)
Zymoseptoria tritici is a filamentous ascomycete fungus that causes Septoria tritici blotch (STB)
disease,one of the most important foliar diseases of wheat in temperate climates. The
infection biology of the fungus is relatively well studied, and analyses of the fully sequenced
genome and various transcriptome, proteome and metabolome datasets produced recently
are beginning to provide many candidate genes and signalling pathways that may have
important roles in STB disease establishment in wheat. One of the major challenges now is to
validate and functionally analyse the contribution of candidate wheat genes with predicted
roles in wheat-Z. tritici interactions. Virus-induced gene silencing (VIGS) is a powerful tool for
transient down-regulation of expression of target genes, allowing moderately high throughput
screening of candidate genes of interest in different wheat genotypes. We have established a
Barley stripe mosaic virus-mediated VIGS system to functionally analyse candidate wheat
genes involved in susceptibility to Z. tritici. Silencing of key genes in photopigment
biosynthesis disrupted the correct temporal regulation of plant cell death responses to Z. tritici
by affecting chloroplast functionality, resulting in more rapid tissue death but reduced asexual
sporulation of the fungus. We present data from on-going studies into the role of BAK1regulated plant cell death during compatible wheat-Z. tritici interactions.
Session 4: Cell biology and host-pathogen interactions FRI-6
LEE Wing (1), RUDD Jason (1), HAMMOND-KOSACK Kim (1), KANYUKA Kostya (1)
A role for BAK1 in the Zymoseptoria tritici-wheat interaction
Zymoseptoria tritici is the causal agent of Septoria tritici blotch (STB) disease, one of the most
important foliar diseases of wheat in Europe. Infection of fully susceptible wheat genotypes
by Z. tritici comprises three main stages; penetration of leaf tissue through open stomata, a
subsequent symptomless phase during which the fungus colonizes the apoplastic space
around the mesophyll cells, and a final so-called necrotrophic phase associated with rapid
induction of host cell death and visible disease lesion formation. The transition from the
symptomless to the necrotrophic phase of infection is known to involve a highly localized form
of programmed cell death (PCD), but the exact mechanisms behind this activation of PCD are
not known. In Arabidopsis, the leucine-rich repeat receptor-like kinase (LRR-RLK) BAK1 is an
important regulator of pathogen-associated molecular pattern (PAMP)-triggered immunity
and of cell death control. BAK1 regulation of these pathways depends on interactions with a
number of other LRR-RLKs, including the cell death regulators BIR1 and SUPPRESSOR OF BIR1
(SOBIR). We have used virus-induced gene silencing to down-regulate expression of the wheat
homologues of BAK1 and SOBIR in wheat leaves prior to inoculation with Z. tritici strain
IPO323. We will present data showing that in the susceptible wheat cv. Riband, BAK1- and
SOBIR-silenced leaves develop more severe STB symptoms, suggesting a role for BAK1 in cell
death regulation in Z. tritici-wheat interactions.
FRI-7
MEHRABI Rahim (1), TAHER MAZANDARANI Fatemeh (2), MALEKI Mojdeh (2)
(1) Seed and Plant Improvement Institute, Agricultural Research, Education and Extension
Organization (AREEO), Karaj, IRran (2) Islamic Azad University, Varamin Branch, Varamin, Iran
Effectiveness of Septoria tritici blotch (Stb) resistance genes to Zymoseptoria
tritici isolates from Iran
Septoria tritici blotch (STB), caused by Zymoseptoria tritici is considered as an important
destructive disease of wheat worldwide as well as Iran. In order to study the virulence spectra
of isolates collected from Fars province on the differential cultivars possessing Stb resistance
genes, pathogenicity tests using 7 isolates were conducted under controlled conditions at
Seed and Plant Improvement Institute in Karaj based on 0-5 scaling system. Out of 126 Z. triticiwheat interactions, 41 specific resistances and 85 susceptible interactions were found. Except
RM186 and RM177 that had similar virulence pattern, the remaining isolates exhibited distinct
virulence pattern indicating that these isolates had genetic differences. Among isolates tested,
isolates RM9, RM175 and RM179 were the least virulent isolates that were pathogenic on 9
out of 18 differential cultivars. Isolates RM28 and RM159 were virulent on 16 differential
cultivars and, thus, were considered as the most virulent isolates. The results showed that
among resistance genes, Stb16/Stb17 presented in M3 cultivar were effective against all
isolates. None of the Stb5, Stb6, Stb7 and Stb8 was effective against isolates tested. These
results can be used in wheat breeding programs for resistance to septoria tritici blotch disease
in Fars province.
FRI-8
ORS Marie-Eva (2), SIAH Ali (1), RANDOUX Béatrice (2), SELIM Sameh (3),
SAHMER Karin (1), COULEAUD Gilles (4), MAUMENÉ Claude (4), REIGNAULT
Philippe (2), HALAMA Patrice (1)
(1) ICV, ISA, Lille, France (2) UCEIV, Université du Littoral Côte d’Opale, Calais, France (3) BPPP, Institut
Polytechnique Lasalle-Beauvais, Beauvais, France (4) Arvalis, Institut du Végétal, Station expérimentale
de Boigneville, Boigneville, France
Efficacy and modes of action of resistance inducers on wheat against
In the current context aiming at reducing the use of conventional pesticides in agriculture,
development of alternative control strategies such as the use of plant resistance inducers is
strongly encouraged. In the present study, we assessed the efficacy and the modes of action
of three resistance inducers (FSOV1, a phosphite-based inducer; FSOV7, a Trichoderma
harzanium protein extract-based inducer; and FSOV10, a cell wall polysacharide-based
inducer) on wheat against Zymoseptoria tritici. The experiments were carried out in the
greenhouse using three-leaf stage plants of the Alixan (susceptible), Premio (moderately
susceptible) and Altigo (resistant) bread wheat cultivars treated with the resistance inducers
two days before inoculation with the Z. tritici T01193 strain. Our results (up to 89 % reduction)
revealed protection efficacies varying with the cultivar and the resistance inducer. Indeed,
FSOV7 induced significant protections on the three cultivars, while FSOV2 was efficient only
on Alixan and Altigo, and FSOV10 only on Premio and Altigo. In planta cytological
investigations revealed no direct effect of resistance inducers on spore germination, except
for FSOV10 which exhibited a slight antifungal effect on Premio and Altigo. A correlation
between protection efficacy and reductions of mesophyll colonization and cell-wall degrading
enzyme activities as well as protease activity, was highlighted. On the other hand, an
elicitation of wheat peroxidase and phenylalanine ammonia-lyase activities in the three
cultivars as well as an induction of the expression of nine defense genes were detected; but
the measured up-regulation levels were not linked to the protection rates, although resistance
inducers clearly activated different defense pathways. Our study showed that the efficacies
recorded were due to plant defense elicitations rather than to a direct antifungal effect and
highlighted the importance of wheat cultivar and resistance inducer when considering wheat
defence induction against Z. tritici as a control strategy.
FRI-9
BENBOW Harriet (1), ZHOU Binbin (1), CHRISTODOULOU Thalia (1), BRENNAN
Ciaran (1), MULLINS Ewen (2), DOOHAN Fiona (1)
(1) UCD School of Biology and Environmental Science and UCD Earth Institute, University College Dublin,
Belfield, Dublin, Ireland (2) Teagasc Crops Research, Carlow, Ireland
Identifying genetic resistance to Septoria tritici blotch in wheat using nextgeneration RNA sequencing.
Within this WHEAT SECURITY project, we will employ next-generation sequencing to identify
candidate genes involved in host resistance to Septoria tritici blotch (STB); the most
devastating foliar disease of wheat in Ireland. Using bulked-segregant analysis (BSA) by RNAseq of a doubled-haploid population of Triticum aestivum cvs. Stigg (resistant) and Longbow
(susceptible), we will sequence RNA of inoculated and control plants in a time series. The time
points (0, 1, 4, 8 and 14 days post inoculation) were chosen to target differential gene
expression between the resistant and susceptible hosts during early infection. In
complement, we will perform BSA by RNA-seq of a Brachypodium distachyon recombinant
inbred population, which segregates for an STB resistance quantitative trait locus. Following
differential expression analysis, interesting candidates will be validated using RT-PCR, and a
set will be chosen for characterisation. Using the most recent gene models available for
wheat, we will identify varietal single nucleotide polymorphism (SNP) markers between the
resistant and susceptible host plants. These putative SNPs will be validated using Kompetative
Allele Specific PCR for their use in breeding programmes.
FRI-10
BRENNAN Ciaran (1), CHRISTODOULOU Thalia (1), MULLINS Ewen (2), DOOHAN
Fiona (1)
(1) UCD School of Biology and Environmental Science and UCD Earth Institute, University College Dublin,
Belfield, Dublin, Ireland (2) Crops Research, Carlow, Carlow, Ireland
Identification of orphan genes that play a role in the wheat response to
Orphans are taxonomically restricted genes and there is increasing evidence that they play a
role in biological adaptation to environmental stress. Recently, our lab demonstrated that a
gene unique to the Pooideae enhances wheat resistance to Fusarium head blight disease. With
between 3-10% of plant genomes comprising of orphan genes, their discovery represents a
veritable untapped mine of potential for combating stress. We are mining wheat
transcriptomic data in order to identify orphan gene candidates that are responsive to
Zymoseptoria tritici, the causal agent of Septoria tritici blotch (STB) disease of wheat. A
microarray chipset, focused on differential expression of a resistant and susceptible host to
an STB infection, was filtered through a custom pipeline to highlight orphan genes involved in
the early infection stages. A total of 634 genes were highlighted as potential orphans
demonstrating greater than 2 fold up or down-regulation by STB when compared to the
control treatment. From this, 7 genes have been selected for gene silencing and subsequent
qPCR to determine their role in the STB disease response.
FRI-11
BRUEGGEMAN Robert (1), RICHARDS Jonathan (1), FRIESEN Tim (2)
(1) Department of Plant Pathology, North Dakota State University, Fargo, ND, USA (2) Cereal Crops
Unit, Northern Crops Science Laboratory, USDA, ARS, Fargo, ND, USA
Specific net form net blotch susceptibility on barley chromosome 6H may be
conferred by different alleles of the Spt1 gene
Net form net blotch (NFNB), caused by the necrotrophic fungal pathogen Pyrenophora teres
f. teres, is a destructive foliar disease of barley. Resistances to P. teres f. teres from diverse
barley lines were characterized and most QTL map to the centromeric region of chromosome
6H. The dominant susceptibility genes Spt.r and Spt.k, (previously known as rpt.k and rpt.r)
located at the 6H locus confer susceptibility to the California P. teres f. teres isolates 6A and
15A in the barley cultivars (cvs) Rika (R) and Kombar (K), respectively. A R×K high-resolution
map was constructed utilizing 2,976 recombinant gametes and the Spt.r/Spt.k region was
saturated with markers. The major Spt.r/Spt.k susceptibility QTL region, designated Spt1, was
delimited to 0.29 cM. Within the delimited region, found on four physical BAC contigs, a
leucine rich repeat receptor like gene containing a predicted N-terminal transmembrane
domain was identified as the best candidate Spt1 gene. Allele analysis of 45 diverse barley cvs
with differential reaction to 15A and 6A showed a correlation between susceptibility to NFNB
isolates 6A and 15A and the presence of the R (Spt1.r) or K (Spt1.k) alleles of the candidate
Spt1 gene. Also, a third Spt1 allele variant that was first identified from the cultivar Morex,
designated Spt1.m, correlates with susceptibility to the Montana P. teres f. teres isolates TA5
and TD10. These data strongly suggesting that the Spt1.r, k and m alleles may interact with
specific necrotrophic effectors produced by diverse P. teres f. teres isolates in an inverse genefor-gene manner.
Session 5: Host Genetics and Resistance Breeding
FRI-12
CAMPANARO Alberto (1), BYRNE Ed (2), SADANANDOM Ari (1)
(1) School of Biological and Biomedical Sciences, South Road, Durham University, Durham, UK (2)
Cereals Biotechnology KWS UK Ltd Church Street, Thriplow, Hertfordshire, UK
Insights into TaWRKY’s role during Septoria tritici blotch in wheat.
Triticum aestivum is the major food source in many parts of the world, providing
approximately 20% of calories consumed by humans. The pathogen Zymoseptoria tritici that
causes Septoria tritici Blotch (STB), is currently the main threat to wheat production, with an
average yield loss of 20%. Therefore, understanding the molecular mechanisms that underpin
Septoria-wheat interaction will be crucial for generating new control strategies against STB.
WRKY transcription factors are important components of signaling in plants, regulating many
molecular mechanisms in response to abiotic and biotic stresses. Published data demonstrate
that there are at least 3 wheat WRKYs (TaWRKY) that show altered expression upon Septoria
infection (Lee et al., 2015). By transiently silencing specific TaWRKYs we want to ascertain the
role of these transcription factors in immune response to STB.
FRI-13
CHRISTODOULOU Thalia (1), BRENNAN Ciaran (1), MULLINS Ewen (2), UAUY
Cristobal (3), DOOHAN Fiona (1)
(1) UCD School of Biology and Environmental Science and UCD Earth Institute, Dublin, Ireland (2)
Teagasc Crops Research, Carlow, Ireland (3) John Innes Centre, Norwich UK
Screening a wheat TILLING population for altered susceptibility to Septoria
tritici blotch disease
Septoria tritici blotch (STB) disease is one of the major challenges faced by wheat breeders.
Reverse genetic approaches such as TILLING (Targeting Induced Local Lesions in Genomes)
offers great potential for improving crop traits via a non-GM approach. We are screening the
wheat cv. Cadenza population in order to identify mutants with altered susceptibility to
Zymoseptoria tritici. To date we have screened 500 mutants. Plants were propagated in John
Innes No.2 compost during the summer of 2015 in a polytunnel, with a temperature of aprox.
20-30 degrees celsius 80% RH during disease development on the flag leaf. The flag leaf of
secondary or tertiary tillers was sprayed with pycnidia of a Dutch strain of Z. tritici (strain
94269) and disease (percentage of leaf area bearing pycnidia) was scored 21 days postinoculation. This phenotypic evaluation highlighted seven lines heterozygous for enhanced
resistance and five homozygous for an extremely susceptible phenotype, with wild type cv.
Cadenza plants displaying a susceptible response. We are currently preparing to screen the
remainder of the cv. Cadenza population for altered STB resistance, while at the same time
we are cultivating and backcrossing (to cv. Cadenza) TILLING lines of interest arising from the
intial screen. Anticipating the sequencing of these lines, we aim to use a combination of exome
sequence data and phenotype analyses of progeny from a backcross with cv. Cadenza to
identify the gene mutations responsible for the altered disease phenotypes.
FRI-14
DALVAND Mohamad (1), SOLEIMANI PARI Mohamad Javad (1), ZAFARI
Dostmorad (1), ROOHPARVAR Ramin (2), TABIB GHAFARI Seyed Mahmoud (3)
(1) Buali university, Hamadan, Iran (2) Seed and plant improvement institute of Iran, Karaj, Iran (3)
Safiabad Agriculture Research center, Dezful, Iran
Reactions of some Iranian bread and durum wheat genotypes to Septoria leaf
blotch
Wheat Septoria leaf blotch disease caused by Zymoseptoria tritici (syn. Mycosphaerella
graminicola) is one of the most important diseases of wheat in Iran and the world. Evaluation
the reaction of wheat genotypes and on the other hand identifying pathogen virulence factors
are necessary for a successful breeding program. The aim of this study was to assess the adult
plant responses of Iranian bread and durum wheat genotypes developed by Iranian seed and
plant improvement institute (ISSI) to Septoria tritici leaf blotch in harm and humid conditions
in the south of Iran. The study was conducted in Khuzestan province of Iran in two years (20132014 and 2014-2015) and included 47 commercial varities, 68 durum and bread elite lines and
26 differential lines whit a local pathogen isolate that was collected on a bread wheat variety
. Taking notes was performed with a modified Saari and Prescott method in double-digit scale
00-99. From a total of 68 wheat genotypes 24 lines were resistant and 44 lines were
susceptible. From Commercial varieties only 5 varieties were resistant. Even the durum
varieties like Behrang and Karkhe were susceptible. Results of differential set showed
pathogen isolates of this region have virulence reactions for stb2, stb3, stb4, stb6, stb7, stb8,
stb9, stb10, stb12, stb13, stb14 and stb18 genes and for stb1, stb5, stb11, stb15, stb16, stb17
genes the reaction was avirulence. This results can be used in wheat breeding programs .In
addition show the importance of the bread isolate virulence on durum varieties.
FRI-15
DALVAND Mohamad (1), ROOHPARVAR Ramin (2), TABIB GHAFARI Seyed
Mahmoud (2)
(1) Safiabad Agriculture Research center, Agricultural Research, Education and Extension Organization
(AREEO), Dezful, Iran (2) Seed and plant improvement institute of Iran, Agricultural Research, Education
and Extension Organization (AREEO), Karaj, Iran
The first report of triticale as host of Septoria tritici blotch in Iran
Zymoseptoria tritici (syn. Mycosphaerella graminicola, Septoria tritici) causes the wheat
disease Septoria tritici blotch (STB). STB is globally distributed and was recently identified as
the most yield reducing disease in European countries with intensive wheat production
(Jorgensenetal. 2014). During March to April 2014, leaf blotch disease was observed on flag
leaf of triticale in Khuzestan province of Iran . The infected leaf samples were transferred into
laboratory and wheat leaves were subjected to fungal isolation. After culturing of infected
tissues on PDA, a pycnidial fungus was isolated and the isolate was identified as Zymoseptoria
tritici. The mono-pycnidial isolates were purified using single spore procedure as described
previously (Abrinbana et al. 2010; Ghaneie et al. 2012). The isolates then were propagated in
YGM (yeast extract 10 g/l, glucose 20 g/l) at 18°C using a rotary shaker. In order to
demonstrate the pathogenicity of the isolates of Septoria obtained from triticale tow
Susceptible wheat cultivars (Taichung 29 and Darab2) and a triticale cultivar were planted in
greenhouse .Then the cultivars were inoculated in the two-leaf stage and 4 weeks after
inoculation pycnidia appeared on leaves and Zymoseptoria tritici was reisolated from infected
leaves. This is the first report of the occurrence of this fungus on triticale in Iran.
FRI-16
DOWNIE Rowena (1), FURUKI Eiko (2), GARDNER Keith (1), MACKAY Ian (1),
OLIVER Richard (2), PHAN Huyen (2), TAN Kar-Chun (2), COCKRAM James (1)
(1) John Bingham Laboratory, NIAB, Cambridge, UK (2) Centre for Crop Disease Management, Curtin
University, WA, Australia
Mapping the wheat Snn3 locus conferring sensitivity to the P. nodorum
necrotrophic effector SnTox3 using an eight founder MAGIC population
The necrotrophic fungus Parastagonospora nodorum is an important pathogen of one of the
world’s most economically important cereal crops, wheat (Triticum aestivum L.). P. nodorum
produces necrotrophic protein effectors that mediate host cell death, providing nutrients for
continuation of the infection process. The recent discovery of pathogen effectors has
revolutionised disease resistance breeding for necrotrophic diseases in crop species, allowing
often complex genetic resistance mechanisms to be broken down into constituent parts. To
date, three effectors have been identified in P. nodorum. Here we use the effector, SnTox3, to
screen 700 progeny from an eight founder multi-parent advanced generation inter-cross
(MAGIC) population, genotyped for 20,600 variable SNP markers. The MAGIC founders
showed a range of sensitivity to SnTox3, with range of sensitivity evident in the progeny.
SnTox3 sensitivity was analysed for heritability and quantitative trait locus analyses was used
to map the Snn3 locus. In addition, SNPs associated with the Snn3 locus were identified and
converted to the KASP genotyping platform, providing breeders and researchers a simple and
cheap diagnostic marker for allelic state at Snn3.
FRI-17
ELLWOOD Simon (1), SCHWEIZER Patrick (2), GE Xintian (1)
(1) Curtin University, Perth, Australia (2) IPK Gatersleben, Saxony-Anhalt, Germany
A mlo-11 variant provides effective broad-spectrum resistance to barley
powdery mildew without deleterious side effects
Recessive mutations in the Mlo gene confer broad spectrum resistance in barley (Hordeum
vulgare) to powdery mildew (Blumeria graminis f. sp. hordei). All alleles discovered to date
provide comprehensive resistance but also show deleterious pleiotropic effects. Recessive
resistance was discovered in Eth295, an Ethiopian landrace, which was developmentally
controlled and quantitative without spontaneous cell wall appositions or extensive necrosis
and loss of photosynthetic tissue. This resistance is determined by only two copies of the
naturally occurring mlo-11 repeat units, compared to 11-12 in commonly grown cultivars and
was designated mlo-11 (cnv2). Copy number-dependent methylation governing relative Mlo
transcript expression corresponded to the observed cytological and macroscopic phenotypic
differences. The methylation is stable rather than de novo. mlo-11 (cnv2) is the only example
of a moderated mlo variant discovered to date and may be a result of natural selection against
the deleterious effects of standard mlo-11.
FRI-18
FERJAOUI Sahbi (1), BEN SLIMEN Rim (3), SBEI Abdenour (1), AMMAR Karim (2),
DREISIGACKER Susanne (2), HAMZA Sonia (3)
(1) CRRGCB, Beja, Tunisia (2) CIMMYT, Texcoco, Mexico (3) INAT, Tunis, Tunisia
Identification and genetic analysis of total resistance to Zymoseptoria tritici at
adult plant stage in Tunisian Durum wheat landraces
Septoria tritici blotch (STB) caused by the fungus Zymoseptoria tritici (syn. Mycosphaerella
graminicola) is currently the most important foliar disease of durum wheat (Triticum turgidum
ssp. durum) in the Mediterranean area particularly in Tunisia, causing up to 50% yield losses
under conducive conditions. STB management is largely done by the application of fungicides;
nevertheless, this method is hampered by the development of fungicide resistance in Z. tritici
populations. Breeding for resistance to STB in durum wheat could provide an effective,
economic and environmentally-safe strategy to reduce yield losses. However, this is limited
by a lack of resistance sources. Thus a set of 283 old Tunisian local durum wheat accessions
was evaluated for resistance to STB under field inoculation with the virulent Tunisian isolate
TunBz-1 and nine resistant accessions were identified. Among this sources, the resistance of
the accession Agili39 to Tunisian isolates TunBz-1 and TunM-1 was studied on different
populations developed from a cross between the resistant Agili39 and the highly susceptible
durum wheat varieties Karim and Khiar. Segregation for resistance showed that a major gene
controls resistance to each isolate in the resistant accession Agili39. Linkage analysis and QTL
mapping allowed the identification of a major QTL for resistance to Z. tritici on chromosome
2BL, peaked at 1.1 cM proximal to Xgmw382 and delimited by the markers Xwmc317 and
Xgpw1214 within an interval of 7.7 cM. This locus explained 64% and 21% of the phenotypic
variation at adult plant stage in reaction to isolates TunBz-1 and TunM-1 respectively. This QTL
is the first locus for STB resistance described in durum wheat.
FRI-19
KARLSTEDT Frances (1), KOPAHNKE Doris (1), ORDON Frank (1)
(1) Julius Kühn-Institute (JKI), Federal Research Center for Cultivated Plants, Institute for Resistance
Research and Stress Tolerance, Quedlinburg, Germany
Mapping of QTL for Septoria tritici resistance in the wheat gene bank
accession HTRI 1410
Zymoseptoria tritici (syn. Septoria tritici), the causal agent of Septoria tritici blotch (STB),
causes yield losses up to 30 - 50% in wheat, globally. Growing of resistant cultivars is the most
cost effective and environmentally friendly way to avoid these losses. In extensive screening
programmes for resistance, the gene bank accession HTRI 1410 turned out to be resistant in
field tests and is actually tested in greenhouse tests against 22 STB isolates carrying virulences
against the 18 STB genes described up to now. In order to get information on the genetic
background of the STB resistance in HTRI 1410, a DH-population consisting of 135 lines derived
from crosses of HTRI 1410 to three susceptible cultivars was generated. Phenotyping was
conducted for the first year in 2015 at three locations in Germany and the area under the
disease progress curve determined. Based on this the average percentage leaf area diseased
ranged from two to twenty. Field trials will be replicated in 2016 and in addition climate
chamber and greenhouse experiments with STB-isolates being avirulent on HTRI 1410 but
virulent on the other parental lines will be conducted. In parallel this population has already
been genotyped by the 90 k iSelect chip and about 10000 SNPs turned out to be polymorphic.
Map construction and QTL analyses based on first years phenotypic data is in progress and
first results of these studies will be presented.
FRI-20
LEBRUN Marc Henri (1), WEAB CONSORTIUM
Wheat effector assisted breeding for resistance to fungal pathogens
WEAB consortium: Thierry LANGIN, INRA GDEC, Clermont-Ferrand, France; Thomas KROJ, INRA BGPI,
Montpellier, France; James COCKRAM, NIAB, UK ; Richard OLIVER, CCDM, Australia; Gert KEMA, PRI,
Netherlands; Romain VALADE, Arvalis, Thiverval-Grignon, France ; Sébastian PRAUD, BIOGEMMA,
Clermont-Ferrand, France; Valérie LAURENT, Florimond-Desprez, Cappelle en Pévèle, France; Laure
Duchalais, RAGT, Louville la Chenard, France; Volker LEIN, CETAC, Estrées-Saint-Denis, France
The discovery that fungal effector proteins are important for infection represents a novel
opportunity for controlling plant diseases. Use of fungal effectors for resistance breeding is a
game-changing technology creating opportunities and innovative methods to identify novel
resistances to fungal diseases in plants. These methods are amenable to high throughput
phenotyping. The recent availability of high-density genetic marker coverage of the wheat
genome allows the mapping of novel resistances identified through such high throughput
phenotyping. We are using necrotrophic protein effectors from Parastagonospora nodorum
(Pn) and toxic proteins from Fusarium graminearum (Fg) and Zymoseptoria tritici (Zt) to detect
resistance genes/QTLs in wheat. Complementary strategies will be used to detect a large array
of resistance mechanisms to fungal effectors. Recombinant necrotrophic protein effectors and
toxic proteins are produced in yeast and the purified proteins are delivered into wheat leaves
by syringe infiltration. Symptom development is scored few days after infiltration. Screening
of 220 elite French wheat cultivars with Pn ToxA, 1 and 3 has highlighted a large number of
cultivars resistant to the 3 necrotrophic effectors, and only few cultivars sensitive to the three
effectors, suggesting that previous breeding for field resistance to Pn (1960-1980) has led to
the accumulation of insensitivity alleles. To validate this hypothesis, we are currently
pathotyping these wheat cultivars with a French Pn isolate producing Tox1 and 3. Mapping of
loci controlling insensitivity to Pn necrotrophic effectors and resistance to Pn isolate will be
performed using genome-wide association analyses. This project will facilitate plant breeding
efforts to select for resistance to important fungal pathogens by providing a toolkit of biomolecular markers.
FRI-21
LIN Min (1), FICKE Andrea (2), COCKRAM James (3), LILLEMO Morten (1)
(1) Norwegian University of Life Sciences, Aas, Norway (2) Norwegian Institute of Bioeconomy
Research, Aas, NORWAY (3) National Institute of Agricultural Botany, Cambridge, UK
Can sensitivity to necrotrophic effectors explain differences in host resistance
to Parastagonospora nodorum blotch in Northern European winter wheat?
Leaf blotch diseases can cause severe yield losses in wheat, and are an important cause of
fungicide use in European wheat production areas. In contrast to many other European
countries, Septoria nodorum blotch (SNB) is the main leaf blotch disease on winter wheat in
Norway. Despite years of intensive breeding efforts, current cultivars are still insufficient in
their resistance to SNB. It is now well documented that P. nodorum can interact with its host
based on an inverse gene-for-gene model (necrotrophic-effector (NE) triggered susceptibility).
Elimination of susceptibility may be an effective breeding strategy to improve cultivar
resistance and reduce fungicide input. In this work, which is part of the ERA-CAPS project
EfectaWheat (2015-2018), we are investigating the role of necrotrophic effectors (NEs) in the
SNB-winter wheat host-pathogen interaction in Northern Europe. Leaf samples have been
collected across wheat fields in Norway, Denmark, Germany and the UK and are the basis of
a representative isolate collection of P. nodorum in Northern Europe. The genetics of host
resistance will be investigated in two eight-parent MAGIC (multiparent advanced generation
inter-cross) populations, consisting of about 500 winter wheat lines each. These have been
planted for field evaluation of adult plant resistance in Norway and the UK, and will be
subjected to inoculations with single spore isolates and infiltration with purified NEs at the
seedling stage in the greenhouse in Norway. QTL mapping of the MAGIC populations and a
Norwegian association mapping panel is expected to identify the main loci segregating for
resistance/susceptibility to SNB. Screening for known NE genes in the collected P. nodorum
isolates, and comparison of the host QTL with known NE-sensitivity loci will determine the role
of these NEs in causing susceptibility to SNB in Northern European winter wheat. Ultimately,
these results will be used to develop molecular tools to eliminate susceptibility loci in the
breeding material and facilitate effective resistance breeding to SNB.
FRI-22
MASCHER Fabio (1)
(1) Agroscope IPV, Nyon, Switzerland
Stability patterns of resistance against leaf and glume blotch in wheat
The ascomycete Phaeosphaeria nodorum can provoke severe infections on both leaves and
glumes of wheat. Leaf blotch can cause the reduction of yield, while infections of the glume
can alter the conformation of the developing grain and reduce its quality for baking and as a
seed. In modern agriculture, the control of the disease relies on measures to prevent the
disease (rotation, use of certified seeds), the treatment with chemical pesticides and the use
of resistant varieties. Resistance against the two diseases is independent one from the other
and mostly quantitative and polygenic. For the appreciation of varietal resistance, stability of
resistance in different environments and years is of utmost interest. The present experiment
reports results of a 7 years experiment at two experimental sites with artificial inoculations
on a set of 18 modern wheat varieties. Overall, it was possible to class the varieties into 4
stability patterns: stable for both diseases, unstable for both diseases, stable for glume blotch,
but not for leaf blotch as well as stable for leaf blotch but not for glume blotch. According to
our results, to arrange a variety into one of the stability classes, the minimal observation
period is four years x environments. The introduction of resistance stability is a major issue
for breeding since also genetically close varieties may display distinct resistance and stability
patterns.
FRI-23
MILLYARD Linda (1), LEE Jack (1), ARI Sadanandom (1)
(1) School of Biological and Biomedical Sciences, Durham University, Durham, UK
Ubiquitination in wheat defence against the Septoria tritici blotch fungus
Wheat is a major food crop for much of the world, and with an ever-increasing population
there is a rising demand to produce more food in a smaller area. Septoria leaf blotch mould
(caused by the fungus Septoria) is a devastating foliar pathogen of wheat, which can lead to a
20% reduction in yield. Plants have had to evolve a multitude of different defence mechanisms
due to their sessile nature. Protein modifications by ubiquitination has been shown to be
central to plant defence. Virus Induced Gene Silencing (VIGS) using BSMV (Barley Stripe
Mosaic Virus) has been used previously to transiently silence wheat gene expression. In this
study VIGS has been used to investigate Triticum aestivum E2 ubiquitin conjugating (TaU)
enzymes. The main focus of this study is TaU4, the E2 function of which has been proven
through ubiquitin charging assays and the active site cysteine identified. The possible function
of TaU4 in the Septoria-wheat interaction was investigated after silencing TaU4 in wheat and
then infecting with Septoria. TaU4 silenced wheat leaves showed a delay in the onset of
Septoria infection symptoms and had reduced pycnidia and spore counts when compared to
the vector only control. It was concluded that TaU4 acts as a negative regulator of defence in
wheat against Septoria fungal infection.
FRI-24
OTHMENI Manel (1), HAMMAMI Zied (1), BARAKET Mokhtar (2), YAHYAOUI
Amor (3)
(1) INRAT, Tunis, Tunisia (2) Centre Régional de Recherche en Grandes Cultures de Beja, Beja, Tunisia
(3) CIMMYT, Texcoco, Mexico
Screening for resistance to Septoria tritici blotch in durum wheat
Given the timeframe (2015-16), CIMMYT’s (WHEAT-CRP) first set of Precision Wheat
Phenotyping Platforms will be set up on a commissioned basis. At the same time, WHEAT-CRP,
with its national partners, wants to make agricultural research and development donors
aware of the essential need for, and value-for-money of, upgrading and modernizing NARS
wheat phenotyping and breeding capacity. The ultimate goal is to maximize genetic gain per
year by getting more, and more diverse improved varieties, faster onto farmers’ fields. High
throughput plant phenotyping will definitely play a role in enhancing genetic gain and
subsequently increasing crop production. Plant phenotyping is the task to capture the
phenotypic variability of huge genetic collections and associate it with the underlying genetic
background. Septoria tritici bloch (STB) disease caused by Zymoseptoria tritici is currently
recognized as the major threat to wheat production especially in the Mediterranean region,
sub-Saharan Africa, Central, West Asia, and North Africa (CWANA) as well as at many other
locations in Europe, North and Latin America. In the tetraploid durum wheat (Triticum
turgidum) little progress in breeding for resistance to STB has been made compared to the
hexaploid bread wheat (Triticum aestivum). Practically all STB resistance genes are in a T.
aestivum background. Hence, the importance of the phenotyping and identifying new
resistance sources to this disease. CIMMYT in collaboration with ICARDA and in partnership
with the Tunisian Ministry of Agriculture (IRESA) launched in Tunisia the precision phenotyping
platform for Zymoseptoria tritici of durum wheat which will serve wheat breeders in the
future. The platform is located at the experimental station of Beja (north-west Tunisia), known
to be a hotspot region of Zymoseptoria tritici of durum wheat. However additional artificial
inoculations are made to ensure good level of infection. Over 2500 wheat accessions from
CIMMYT (1067 accessions), ICARDA (249 accessions), INRAT (365 accessions), INAT (272
accession), and CRRCG (540 accession) as well as material for graduate student research were
screened. First year results seem to be encouraging to expand the phenotyping and serve
global community. Despite the lack of rain during the month of April, the results obtained very
informative at least to detect the highly susceptible accessions. Among the 1583 accessions
of durum wheat tested, the overall levels of resistance were classified as follows: 31%
resistant, 22 % moderate resistant and 47% susceptible. Detailed results and variability within
and among nurseries will be discussed.
FRI-25
POURANHAJI SHARABIYANI Maryam (1), ROOHPARVAR Ramin (2), TORABI
Mohammad (1)
(1) Department of Plant Pathology, College of Agricalture, Islamic Azad University, Varamin, Pishva
Bramch, Varamin, Tehran, Iran (2) Seed and Plant Improvement Institute (SPII), Department of Cereal
Research, Cereal Pathology Unit, Karaj, Alborz, Iran
Efficacy of wheat Stb resistance genes against Zymoseptoria tritici isolates in
Iran
In this study, following isolation and purification of nineteen isolates of the wheat fungal
pathogen Zymoseptoria tritici, the isolates were separately inoculated on seedlings of 26
wheat differential cultivars carrying different Stb resistance genes (Stb1-18). Virulence pattern
of the isolates were determined on 18 Stb genes based on the cultivars' reaction as percentage
of pycnidial coverage on leaf surface at 21 days post inoculation (dpi). The results indicated
that all Z. tritici isolates were avirulent on Stb16, while they were virulent on the genes Stb2,
Stb6, Stb13 and Stb14. Only the isolate 92005 showed virulence on Stb15. Regarding
considerable resistance pattern of the cultivars carrying Stb16 and Stb15, these genes could
be used in breeding programs to produce wheat cultivars resistant to Septoria leaf blotch. The
high pathotype variation observed in this study could be a strong indication for a high genetic
diversity among Z. tritici populations in Iran.
FRI-26
POURANHAJI SHARABIYANI Maryam
HASSANPOUR HOSNI Maghsoud (3)
(1),
ROOHPARVAR
Ramin
(2),
(1) Department of Plant Pathology, College of Agricalture, Islamic Azad University, Varamin, Pishva
Branch, Varamin, Tehran, Iran (2) Seed and Plant Improvement Institute (SPII), Department of Cereal
Research, Cereal Pathology Unit, Karaj, Alborz, Iran
Resistance to Septoria tritici Blotch (STB) in Iranian rainfed wheat breeding
programs
Cultivation of resistant wheat cultivars is considered as the most important, economical and
environment-friendly method to control STB disease. In order to identify resistant wheat
cultivars, seedling reaction of 214 rainfed advanced bread and durum wheat genotypes was
assessed to a high virulent Z. tritici isolate (virulent on 15 Stb genes) based on percentages of
necrotic and pycnidial coverage on leaves at 21 days post inoculation (dpi). Analysis of
variance showed significant differences among the genotypes (P < 0.01), indicting a variation
in their responses to Z. tritici infection. Data showed that 34 and 11 genotypes were highly
resistant and resistant to STB, respectively. Based on the results of this study, the genotypes
with acceptable resistance levels to STB could be screened for the next steps and/or utilized
as sources of resistance in dry land wheat breeding programs.
FR-27
RUUD Anja Karine (1), FICKE Andrea (2), FRIESEN Tim (3), LILLEMO Morten (1)
(1) Norwegian University of Life Sciences, ÅS, NORWAY (2) Norwegian Institute for Bioeconomic
Research, ÅS, NORWAY (3) Biosciences Research Laboratory, USDA, ARS, FARGO, ND, USA (4)
Department of Plant Pathology, North Dakota State University, FARGO, ND, USA
Necrotrophic effectors and sensitivity genes in the wheat-Parastagonospora
nodorum pathosystem under field conditions
Leaf blotch diseases in wheat can cause significant yield losses and reduce grain quality. In
Norway, Parastagonospora nodorum is the dominant causal agent. Research spanning the last
decade suggests that very specific, inverse gene-for-gene actions are involved in the
pathosystem. Many host-selective necrotrophic effectors (NEs) and corresponding sensitivity
(Snn) genes in the host have already been identified. The effectors induce cell death in the
host, which enables the pathogen to invade the dead tissues. The focus of our project is to
identify and map NE/Snn-interactions in Norwegian pathogen population and wheat material,
and to determine the importance of these interactions under field conditions. An genome
wide association (GWAS) mapping panel of Norwegian commercial lines, breeding material
and international cultivars (MASbasis) and several bi-parental spring wheat populations
including SHA3-CBRD x Naxos and Soru1 x Naxos have been screened in a mist irrigated field
nursery over several years, and resistance data corrected for confounding traits (height and
earliness). QTL have been detected on chromosomes 1B, 2AS, 3B, 5BS, 5BL, 7A and 7B in
SHA3/CBRD x Naxos, and on 1A, 2B, 4B, 7A and 7B in Soru#1 x Naxos. Greenhouse trials have
showed that some of these QTL also are significant at seedling stage and caused by NEs
including Tox3, and possibly also host-nonspecific mechanisms. Results also indicate that QTL
on 7A and 7B may be validated in Soru#1 x Naxos and that a QTL on 7B in the seedling stage
may be caused by a novel NE. Screening of Norwegian P. nodorum isolates revealed a higher
proportion of ToxA-producing isolates than for previously published data from Europe. The
results from Tox-screening and association mapping of MAS basis will explain whether this
deviation is caused by Tsn1-sensitivity in Norwegian commercial cultivars. Further work will
include characterization of putative new NEs, fine mapping of the chromosomal regions of
interest and development of diagnostic markers for practical breeding.
FR-28
SEE Pao Theen (1), MOFFAT Caroline (1), OLIVER Richard (1)
(1) Centre for Crop and Disease Management, Department of Environment and Agriculture, School of
Science, Curtin University, Perth WA6102, Perth, Australia
Evaluation of Australian spring wheat seedling resistance to ToxA knockout
Pyrenophora tritici-repentis race 1
The foliar wheat disease tan spot, also known as yellow leaf spot is caused by the necrotrophic
dothideomycete pathogen Pyrenophora tritici-repentis. Since the emergence of tan spot
disease globally in 1970s and 1980, this disease has become one of the most concerned crop
diseases in Australia causing up to 30% yield lost in susceptible varieties. P. tritici-repentis
produces multiple host-selective toxins (HST) and one of the HST that is well-studied in this
pathogen is ToxA, a proteinaceous effector. The sensitivity of ToxA in the host is conferred by
a single gene Tsn1. The significance of ToxA-Tsn1 interaction in the development of tan spot
disease is well-documented in the P. tritici-repentis-wheat pathosystem. Studies have shown
that host sensitivity to ToxA has been found to be associated with disease susceptibility.
Conversely, insensitivity to ToxA has been associated with tan spot resistance. In this study,
commercial hexaploids spring wheat varieties were evaluated for their disease response to
the race 1 P. tritici-repentis mutant strain lacking the ToxA gene. Observation of tan spot
symptoms between wild-type and toxa mutant strains revealed complex pathogen-host
interactions with the outcome of the disease responses that are dependent on the wheat
genotypes.
FRI-29
DREISIGACKER Susanne (1), HE Xinyao (1), SINGH Pawan (1)
(1) CIMMYT, Texcoco, MEXICO
Adult-plant resistance to Septoria tritici blotch in two bread wheat mapping
populations
Most genetic studies for Septoria tritici blotch (STB) resistance in wheat were conducted at
the seedling stage, but it is important to investigate the resistance mechanisms at adult-plant
stage to enhance our understanding on STB resistance. Two spring wheat mapping
populations with 200 and 193 F6:7 progenies were used in the current research to study the
genetics and map adult-plant resistance to STB under field conditions in different
environments. The two populations had the same susceptible parent, the Moroccan variety
NASMA, while the resistant parents were two CIMMYT resistant lines, IAS20*5/H567.71 and
RPB709.71/COC. Around 100 SSR and SNP markers were included in the linkage map for each
population, which had shown polymorphism between the contrasting bulks in a preliminary
experiment. Field experiments were carried out in Toluca and Boximo in 2010 and 2011
cropping seasons. Phenotypic data demonstrated continuous distributions of the RILs in terms
of disease severity, indicating a typical quantitative inheritance of STB resistance in both
populations. QTL mapping revealed five resistance loci on chromosomes 1BS, 3AL, 5AL and
7AS in the two populations, they expressed stably across environments in an additive mode
and explained between 4 and 27% of the phenotypic variation. Epistatic interaction was not
observed. The QTL on chromosomes 1BS and 7AS are likely to be allelic to the known STB
resistance genes Stb3 and Stb11. Low cost KASP assays were developed as flanking markers
for all five QTL. The assays are being used to screen sets of advanced CIMMYT bread wheat
lines to determine the presence and frequency of the observed QTL and validate if they might
facilitate a MAS program.
FRI-30
JULIANA Philomin (2), SINGH Pawan (1), CROSSA Jose (1), SINGH Ravi (1),
SORRELLS Mark (2)
(1) CIMMYT, Texcoco, Mexico (2) Plant Breeding and Genetics Section, School of Integrative Plant
Science, Cornell University, Ithaca, NY , USA
Prediction models to determine the breeding value for Septoria tritici blotch,
Septoria nodorum blotch and tan spot resistance in wheat
The leaf spotting diseases in wheat cause huge economic losses and has been a major
challenge to breeders. One promising approach that could accelerate the gain from selection
in breeding for disease resistance is « genomic prediction » which utilizes dense genome-wide
markers to estimate the breeding values for quantitative traits. Our objective was to compare
different prediction models to determine the breeding values of CIMMYT"s 45th and 46th
International Bread Wheat Screening Nursery (IBWSN) entries for Septoria tritici blotch (STB),
Septoria nodorum blotch (SNB) and tan spot (TS) resistance. The 267 lines in the 45th IBWSN
and 305 lines in the 46th IBWSN were phenotyped in replicated trials at Toluca and El Batan
(Mexico) and genotyped using Genotyping By Sequencing (GBS) markers. We observed that
the prediction accuracies were the highest for seedling resistance to TS (0.72±0.08) and SNB
(0.51±0.07), followed by adult plant resistance (APR) to TS (0.43±0.06) and STB (0.42±0.09).
Among the models, the model with QTL-linked markers as fixed effects gave the lowest mean
prediction accuracies (0.27±0.12), while Reproducing Kernel Hiebert Spaces (RKHS) with
markers and pedigree gave the highest (0.5±0.11). The Genomic-BLUP (0.48±0.11); GenomicBLUP mixed model (0.45±0.13); Bayesian Ridge Regression (0.49±0.11); Bayes A (0.49±0.10);
Bayes B (0.49±0.10); Bayes Cπ (0.49±0.10); Bayesian LASSO (0.48±0.10); RKHS markers
(0.48±0.11) and RKHS pedigree (0.46±0.10) yielded similar accuracies. Overall, our results
indicate that (i) the prediction accuracies depend on the genetic architecture of resistance,
the number and effect size of loci affecting the trait (ii) using genome-wide markers is
advantageous than using only QTL-linked markers (iii) markers did not provide significant
advantage over pedigree in these populations due to small family sizes (iv) using both pedigree
and markers results in slightly higher accuracies. We hope that implementing genomic
prediction in breeding for complex disease resistance would help to achieve higher accuracy,
lower cost and rapid gains from selection.
FRI-31
TABIB GHAFFARY Seyed Mahmoud (1), KEMA Gert H.J. (2)
(1) Safiabad Agricultural Research Center, Dezfoul, Iran (2) Wageningen University, Biointeractions &
Plant Health Plant Research International, Wageningen, The Netherlands
Gene action and selection in breeding for resistance to Zymoseptoria tritici
Septoria tritici blotch (STB) caused by Zymoseptoria tritici is a globally important wheat foliar
disease, resulting up to 50% yield damage under epidemic condition. Disease management
depends on chemical control and breeding for resistance, but the former is unstable due to
frequently emerging fungicide resistance. Developing new resistant germplasm is the
alternative and most environmentally friendly approach for STB control. However; selection
is hampered by appropriately differentiating resistant from susceptible plants during the
selection process. Particularly since STB has a quantitative appearance under field conditions,
due to the genetically diverse field populations of the pathogen. Hence, such estimates are
essentially only possible under controlled conditions while working towards marker assisted
breeding. QTL analyses of two developed DH populations, Apache/Balance and FD3/SE3,were
conducted at the seedling stage using two Z. tritici isolates: IPO323 (for both population) and
IPO87016 (only for Apache/Balance). Using IPO323 in the Apache/Balance and FD3/SE3
populations, we detected a major QTL on chromosome 3A, associated to DArT markers wPt0836and wPt-745076, repectively, which is most likely resistance gene Stb6. With isolate
IPO87016 we identified a major QTL on chromosome 1B linked to DArT marker wPt-2019 in
the Apache/Balance population, which is in the vicinity of Stb11, based on association with
marker Xbarc008 in the publicly available Canon/Reeder map. We concluded that cvs. Balance
and Apache contributed Stb6 and Stb11, respectively.SE3 contributed Stb6 in the FD3/SE3
population. In the Apache/Balance population, average scores for all progeny with Stb6 were
25%N and 1%P. In the FD3/SE3 population these scores were 11%N and 2%P.With IPO87016
lines carrying Stb11 in the Apache/Balance population these scores were 37%N and 12%P.
Hence, G/E interactions greatly hamper decisive selection criteria and further research, ideally
cloning of these genes, will enable us to precisely understand how gene action is determined
by genetic background and environmental factors. For practical reasons, marker-assisted
breeding is the only feasible approach to efficiently select resistance progeny in a practical
breeding program.
Session 5: Host genetics and resistance breeding FRI-32
TABIB GHAFFARY Seyed Mahmoud (1), KHODARAHMI Manouchehr (2), JALAL
KAMALI Mohammad Reza (3), SINGH Pawan K. (4)
(1) Safiabad Agricultural Research Center, Dezfoul, Iran (2) Seed and plant improvement institute (SPII),
Karaj, IRAN (3) CIMMYT- Iran, Karaj, Iran (4) CIMMYT, ElBatán, MEXICO
Septoria Resistance Screening of Advance CIMMYT Lines in Southwest of Iran
Septoria tritici blotch (STB) caused by Zymoseptoria tritici is a worldwide wheat foliar disease,
resulting up to 50% yield damage in epidemic condition. Chemical control and breeding for
resistance are two approaches to manage disease, in which former is less stable due to
frequently emerging fungicide resistant strains. International wheat and maize improvement
center (CIMMYT) regularly is releasing wheat nurseries, comprised advance breeding lines
that improved against different biotic /abiotic stresses and spread them all over the world to
imposes breeding lines in real stress situation for final selection. International Septoria
Observation Nursery (ISEPTON) is a set of advance lines targeting area where STB has known
as a major biotic threat including Khuzestan and Ilam provinces in southwest of Iran. Serial
ISEPTON 22nd as well as 23rd were planted and inoculated at flag leaf emerging stage in
2012-2013 and 2013-2014 using SEPIRN11001 and SEPIRN11002 strains, respectively.
Screening was conducted at Safiabad agricultural research center (320 15" 37» N - 480 25"
98» E- 82.9 m ASL) where each nursery contained 83 wheat genotypes, including 52 advance
lines, 28 differential set of Stb gene carrier and three susceptible checks. In 22nd ISEPTON
(2012-2013) disease symptom ranged between 0 and 80 percent of leaf area bearing necrosis
and pycnidia, when disease symptom on local susceptible check ( Darab 2) ranged 50-60
percent. Isolate SEPIRN11001 circumvented differential cultivars, carrying Stb2, 3, 4, 6, 7, 10,
12 genes, whereas others carrying Stb5, 8, 9, 11, 13, 14, 16 and Stb17 indicated resistance
phenotype against applied isolate. In 23rd ISEPTON (2013-2014) Pycnidia in necrosis lesion
ranged between 13 and 80 percent of leaf area. Disease symptom on local susceptible check
( Darab 2) recorded in range of 75-79 percent. Applied Isolate SEPIRN11002 was aggressive on
differential set including M3 and KM20, carrying Stb16 and Stb17, however the disease
symptoms only was observed on the lowest leaves with max 30% pycnidia. Although, the
resistance gene Stb16, reported in 2012, known as with range resistance gene, extraordinary
observation on KM7 (Stb16)- SEPIRN11002 interaction indicated up to 75% of necrosis bearing
pycnidia on flag leaf .
FRI-33
VAGNDORF Nana (1), JUSTESEN Annemarie Fejer (1), ORABI Jihad (2), ANDERSEN
Jeppe Reitan (2), JAHOOR Ahmed (2), JØRGENSEN Lise Nistrup (1)
(1) Department of agroecology, Aarhus University, Slagelse, Denmark (2) Nordic Seed A/S, Odder,
Denmark
Improvement of resistance against Septoria Leaf Blotch caused by the fungus
Zymoseptoria tritici in Danish winter wheat cultivars
Septoria tritici blotch (STB) caused by the ascomycetes fungus Zymoseptoria tritici (syn.
Mycosphaerella graminicola), is a devastating disease causing major yield losses in winter
wheat every year in particularly in the North Western part of Europe. National yearly
monitoring of STB attack in winter wheat varieties is carried out at several sites in Denmark
providing knowledge on degree of susceptibility and need for fungicide input. Data indicates
that a dynamic flow in disease susceptibility of the varieties exists across sites and years. In a
specific study, field trials with 184 winter wheat varieties from Northern Europe were assessed
for their susceptibility towards STB over a period of three years on three locations. Some
ranking can be seen based on the assessments, but the results also indicate a large variation
between years and locations, a variability which is in agreement with the Danish national
trials. Thus, the disease is seen to be dynamic and varies to some extend in aggressiveness
across years and sites. Results from several years of national field trials of commonly grown
Danish cultivars show that there is a shift towards a higher STB susceptibility, when cultivars
are becoming widespread and commonly grown. The sexual reproduction of Z. tritici is known
to facilitate a shift in aggressiveness of the populations, making the varieties more susceptible
to STB attack as they increase in area. To avoid this, varieties with a more durable resistance
are required. The sexual reproduction of Z. tritici enables the fungus to quickly overcome
single resistance genes, e.g. qualitative resistance. In addition, varieties with several QTL,
quantitative resistance, associated with STB resistance, will provide a more durable resistance.
Therefore, pyramiding of several QTL is recognized as a solution to minimize the shift towards
higher susceptibility. Genotyping of the 184 winter wheat varieties using a 15K SNP wheat
array followed by association mapping identified four QTL associated with resistance to STB.
Future studies will reveal if pyramiding of these four QTL in new varieties will provide a more
durable resistance towards STB. Lastly, with the aim of analyzing diversity and population
structure, 177 Z. tritici isolates mainly from Denmark were analysed using molecular markers
with focus on possible differences between years, localities and varieties from which they
were sampled.
FRI-34
WALCZEWSKI Jakub (1), ARSENIUK Edward (1), OCHODZKI Piotr (1)
(1) Breeding and Acclimatization Institute, NRI, Radzików, Radzikow, Poland
Contribution of proteinaceous toxins in Parastagonospora nodorum blotch
development in wheat.
Parastagonospora nodorum is a necrotrophic pathogen of all assimilative green parts of wheat
and triticale as well as of other cereals and grasses. Oval or lens-shaped, first chlorotic and
later in the season redbrown spots develop along the leaf blade and sheath and affect the
entire leaf and/or glume and awns. With development of the disease, called Septoria nodorum
leaf and glume blotch, on necrotic lesions appears pycnidial sporulation. Destruction of green
plant parts affects adversely photosynthesis, what results in grain yield loss, quantitative and
qualitative in nature. In past several years appeared quite a number of reports on
proteinaceous host selective toxins produced by P. nodorum in affected plant tissue. These
play crucial role in induction of tissue necrosis. Toxins interact with specific host genes.
Positive recognition with dominant allele in affected plant leads to necrosis induction, while
absence of dominant allele causes toxin insensitivity. So far, eight pairs of P. nodorum
toxin/host gene were reported and described. Tests conducted under controlled environment
as well as field conditions confirmed that protein toxins are important factors in P. nodorum
leaf and glum blotch of wheat. Examination of ToxA, Tox1 and Tox3 genes of P. nodorum
isolates collected in Poland. Evaluation of Polish wheat varieties and breading lines reactions
to semi purified Tox3. Genes coding Tox1 and Tox3 toxins are significantly more frequent in
Polish isolates than the ToxA gene. Majority of tested isolates contain both Tox1 and Tox3.
Seedling leaves of a number of Polish wheat varieties were infiltrated with
chromatographically purified preparations of Tox3. 22% of wheat seedlings were susceptible.
Toxin resistance was compared with P. nodorum phenotypic resistance and significant
correlation between these two types of reactions was found. The main purpose of the project
was to screen Polish wheat germplasm lines against susceptibility to known proteinaceous
toxins produced by P. nodorum and to validate their contributions in SNB development in
wheat and triticale. Data on this poster represent the first step undertaken to achieve our
goal. In upcoming years we are planning to purify more effectors and to continue genotyping
of the cereal lines.
FR-35
WONNEBERGER Ronja (1), FICKE Andrea (2), VIVIAN-SMITH Adam (2), FRIESEN
Tim (3), LILLEMO Morten (1)
(1) Department of Plant Sciences, Norwegian University of Life Sciences (NMBU), Ås, Norway (2)
Norwegian Institute of Bioeconomy Research (NIBIO), Ås, Norway (3) USDA-ARS, Northern Crop Science
Laboratory, Fargo, USA
Identification of molecular mechanisms in the Drechslera teres – barley
pathosystem and population structure of a Norwegian D. teres population
The necrotrophic fungus Drechslera teres causes net blotch disease in barley by secreting
necrotrophic effectors (NEs) which, in the presence of corresponding host susceptibility
factors (SF), act as virulence factors in order to enable host colonization. At present the
resistance within most Norwegian cultivars is insufficient. This study aims at detecting QTL
associated with resistance and susceptibility in the Nordic barley breeding material and at
discovering new NE & SF interactions. This knowledge together with an understanding of the
genetic background of the Norwegian net blotch population will be utilized to speed up
resistance breeding. Resistance of a segregating mapping population of a cross between the
closely related Norwegian varieties Arve and Lavrans to three Norwegian D. teres isolates was
assessed at seedling stage in the greenhouse and in adult plants in the field. QTL mapping
revealed four major QTL on chromosomes 4H, 5H, 6H and 7H. The resistance source for the
QTL on 5H, 6H and 7H are contributed by the resistant parent Lavrans, while the resistance on
4H stems from the susceptible parent Arve, The 5H and 6H QTL accounted for up to 47% and
14,1% of the genetic variance, respectively, and were found both in seedlings and adult plants
with the latter QTL being an isolate-specific association. The high correlation of seedling and
adult resistance (R2=0,49) suggests that components of adult plant resistance can be
predicted already at the seedling stage. Selected isolates and their culture filtrates will be
screened on selected barley lines to characterize novel NE - SF interactions and to map the
corresponding sensitivity loci. Effector protein candidates will be purified and further analysed
to verify their effect on disease development. Additionally, 365 Norwegian D. teres isolates
and a selection of globally collected isolates are currently being ddRAD genotyped in order to
obtain SNP markers to study the genetic diversity and population structure of the current
Norwegian fungal population. This data will also allow us to perform Genome Wide
Association Studies (GWAS) to identify potential novel NE genes.
FRI-36
ZHOU Binbin (1), CHRISTODOULOU Thalia (1), BRENNAN Ciaran (1), FEECHAN
Angela (2), DOOHAN Fiona (1)
(1) UCD School of Biology and Environmental Science and UCD Earth Institute, Dublin, Ireland (2) UCD
School Of Agriculture and Food Science and UCD Earth Institute, Dublin, Ireland
Identification of wheat proteins involved in the host response to
Septoria tritici blotch (STB) disease is the most significant threat to yield in most wheat
growing regions. To identify the resistance gene in wheat, seven orphan genes have been
selected from Zymoseptoria tritici and wheat interaction microarray database. We have
selected orphan genes that play a role in the wheat response to STB disease. Orphans are
taxonomically restricted genes and there is increasing evidence that they play a role in
biological adaptation to environmental stress. The majority of orphan genes encode the
orphan protein which have unknown function. In order to identify the interacting proteins of
these orphan proteins, a yeast two hybrid library (Y2H) has been constructed. The third leaf
of Triticum aestivum cvs. Stigg (resistant) and Longbow (susceptible) were inoculated with a
mixed isolate inoculum of Z. tritici. Leaves were collected at various time points postinoculation, covering both the asymptomatic phase and the disease establishment phases. All
the sample were bulked for RNA extraction. Y2H library construction and screening are being
performing by Hybrigenics Services. The orphan proteins will be used as bait to screen the
cDNA expression Y2H library. In addition, a Z. tritici candidate effector has been identified by
our collaborating lab. This effector will also be used as a bait to screen the Y2H library. The
host interacting proteins of both orphan proteins and the effector target proteins will be
identified and characterized.
AUTHOR INDEX
A
AJIGBOYE Olubukola................................................... 106
AKROUTI Waad ............................................................. 25
AOUINI Lamia ............................................................... 65
AVROVA Anna ............................................................... 50
FICKE Andrea ................................................................ 23
FONES Helen ................................................................. 51
FRAAIJE Bart ................................................................. 19
FRANCKI Michael .......................................................... 61
FREITAG Michael .......................................................... 13
FRIESEN Tim .......................................................... 32, 100
G
B
BANCAL Marie-Odile ..................................................... 29
BARTOSIAK Slawomir ................................................. 107
BEL HADJ CHEDLI Rim ................................................... 72
BENBOW Harriet ......................................................... 112
BENSLIMANE Hamida ................................................... 73
BENTATA Fatiha ............................................................ 67
BOIXEL Anne-Lise .................................................... 30, 74
BOUKEF Sameh ............................................................. 75
BRENNAN Ciaran ........................................................ 113
BROWN James .............................................................. 60
BRUEGGEMAN Robert ................................................ 114
BRUNNER Patrick .......................................................... 33
GARIN Guillaume .......................................................... 27
GENISSEL Anne ............................................................. 17
GOODWIN Stephen ...................................................... 62
GOUT Lilian ................................................................... 16
H
HABIG Michael ............................................................. 35
HARTMANN Fanny ..................................................... 101
HASSINE Marwa ........................................................... 80
HAUEISEN Janine .......................................................... 53
HAWKINS Wayne.......................................................... 81
HESS Michael ................................................................ 41
HOURCADE Delphine .................................................... 63
C
CAMPANARO Alberto ................................................. 115
CHAUDHARI Yogesh...................................................... 96
CHRISTODOULOU Thalia ............................................. 116
COLLIN François ............................................................ 76
CONFAIS Johann ........................................................... 68
CROLL Daniel ................................................................. 15
CSUKAI Michael ............................................................ 77
D
DALVAND Mohamad .......................................... 117, 118
DHILLON Braham .......................................................... 18
DOOLEY Hilda................................................................ 97
DOWNIE Rowena ........................................................ 119
DUVIVIER Maxime ........................................................ 78
E
ELLWOOD Simon ......................................................... 120
F
FARIS Justin ................................................................... 43
FEODOROVA-FEDOTOVA Liga ...................................... 79
FERJAOUI Sahbi........................................................... 121
J
JØRGENSEN Lise Nistrup............................................... 24
K
KARLSTEDT Frances .................................................... 122
KAZEMI Homayoon ...................................................... 82
KERDRAON Lydie .......................................................... 83
KETTLES Graeme ........................................................... 44
KING Robert .................................................................. 48
KLITTICH Carla .............................................................. 84
KROJ Thomas ................................................................ 57
L
LE MIRE Geraldine ........................................................ 85
LEBRUN Marc Henri .................................................... 123
LEE Wing ............................................................. 108, 109
LILLEMO Morten ......................................................... 124
M
MACCAFERRI Marco ..................................................... 64
MADARIAGA Ricardo ................................................... 86
MASCHER Fabio .......................................................... 125
MATUSINSKY Pavel ....................................................... 87
McDONALD Megan....................................................... 34
MEAD Oliver.................................................................. 52
MEAMICHE NEDDAF Hayet........................................... 69
MEHRA Lucky ................................................................ 98
MEHRABI Rahim ........................................... 38, 102, 110
MEJRI Samara ............................................................... 88
MILGATE Andrew .......................................................... 22
MILLYARD Linda .......................................................... 126
MIRZADI GOHARI Amir ................................................. 45
MÖLLER Mareike .......................................................... 36
O
OLIVER Richard P .......................................................... 11
OTHMENI Manel ......................................................... 127
P
PALICOVÁ Jana ............................................................. 70
PALMA-GUERRERO Javier............................................. 47
PEDRO Helder ............................................................... 49
PRODI Antonio ........................................................ 89, 90
R
RAY Rumiana ................................................................ 54
REHFUS Alexandra ........................................................ 99
ROOHPARVAR Ramin ................................. 103, 128, 129
RUDD Jason ................................................................... 37
RUUD Anja Karine ....................................................... 130
S
SADANANDOM Ari........................................................ 55
SAEED Khaldoon ........................................................... 91
SAINTENAC Cyrille ......................................................... 59
SANCHEZ VALLET Andrea.............................................. 46
SEE Pao Theen ............................................................. 131
SIAH Ali ............................................................... 104, 111
SIDHU Yaadwinder ....................................................... 39
SINGH Pawan ..................................................... 132, 133
SOMAI Lamia ................................................................ 92
STEUERNAGEL Burkhard .............................................. 56
STUKENBROCK Eva H.................................................... 12
SUFFERT Frédéric .......................................................... 28
T
TABIB GHAFFARY Seyed Mahmoud ................... 134, 135
TAN Kar-Chun ............................................................... 42
TARANTO Adam ........................................................... 58
TILEY Anna .................................................................. 105
TORRIANI Stefano ........................................................ 20
TRABELSI Imen .............................................................. 93
V
VAGNDORF Nana ....................................................... 136
VALADE Romain ........................................................... 31
VIDAL Tiphaine ....................................................... 26, 94
W
WALCZEWSKI Jakub.................................................... 137
WALKER Anne-Sophie................................................... 21
WELCH Thomas............................................................. 71
WIECZOREK Thies Marten ............................................ 95
WONNEBERGER Ronja ............................................... 138
Y
YEMELIN Alexander ...................................................... 40
Z
ZHOU Binbin ............................................................... 139
ACKNOWLEDGEMENTS
The 9th International Symposium on Septoria Diseases of Cereals would like to acknowledge
the following companies and organizations for their generous support.
GOLD
BRONZE
PREMIUM
AJIGBOYE
AKROUTI
ALBERTO
AOUINI
NOM
PRENOM
Olubukola
Waad
Campanaro
Lamia
AVROVA
BANCAL
BANCAL
BARTOSIAK
Anna
Pierre
Marie-Odile
Slawomir
BEL HADJ
BEN KRIMA
BENBOW
BENSLIMANE
Rim
Safa
Harriet
Hamida
BIERI
BIRD
BLUHM
BOIXEL
BRADSHAW
BRANDES
BRENNAN
BROWN
BRUEGGEMAN
Stéphane
Nicholas
Burt
Anne-Lise
Rosie
Welf
Ciaran
James
Robert
BRUNNER
BRYANT
BRYSON
CAMPANARO
CHAOUCH
CHAUDHARI
CHRISTODOULOU
COLLIN
CONFAIS
Patrick
Ruth
Rosie
Alberto
Sejir
Yogesh
Thalia
François
Johann
AD1
University of Nottingham
INAT
Wageningen URWageningen University
James Hutton Institute
INRA
INRA/AgroParisTech
Plant Breeding and
Acclimatization Institute NRI
INAT
INRA
University College Dublin
Ecole Nationale Supérieures
d'Agronomie(National High
college of Agriculture)
Syngenta
KWS UK
University of Arkansas
INRA
Massey University
Belchim Crop Protection
John Innes Centre
North Dakota State
University
ETH Zurich
RAGT Seeds Ltd
BASF
Durham University (UK)
Limagrain Europe
University of Exeter
UMR INRA AgroParisTech
INRA
PAYS
UNITED KINGDOM
TUNISIA
UNITED KINGDOM
THE NETHERLANDS
EMAIL
[email protected]
[email protected]
[email protected]
[email protected]
UNITED KINGDOM
FRANCE
FRANCE
POLAND
[email protected]
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[email protected]
TUNISIA
FRANCE
IRELAND
ALGERIA
[email protected]
[email protected]
[email protected]
[email protected]
SWITZERLAND
UNITED KINGDOM
UNITED STATES
FRANCE
NEW ZEALAND
BELGIUM
IRELAND
UNITED KINGDOM
UNITED STATES
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
SWITZERLAND
UNITED KINGDOM
GERMANY
UNITED KINGDOM
FRANCE
UNITED KINGDOM
IRELAND
FRANCE
FRANCE
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
COUSIN
Arnaud
BASF France Division Agro
FRANCE
[email protected]
CROLL
CSUKAI
DALVAND
DHILLON
DOOLEY
DOWNIE
DUVIVIER
Daniel
Michael
Mohamad
Braham
Hilda
Rowena
Maxime
ETH Zurich
Syngenta
SWITZERLAND
UK
IRAN
USA
IRELAND
UNITED KINGDOM
BELGIQUE
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
ELLWOOD
ENGELEN
FARIS
FEODOROVA-FEDOTOVA
Simon
Steven
Justin
Liga
AUSTRALIA
BELGIUM
UNITED STATES
LATVIA
[email protected]
[email protected]
[email protected]
[email protected]
FERJAOUI
Sahbi
TUNISIA
[email protected]
FICKE
Andrea
NORWAY
[email protected]
FLAK
Michal
GERMANY
[email protected]
FONES
FRAAIJE
FRANCKI
Helen
Bart
Michael
UK
UK
AUSTRALIA
[email protected]
[email protected]
[email protected]
FREITAG
FRIESEN
GARIN
GENISSEL
GOODWIN
Michael
Tim
Guillaume
Anne
Stephen
UNITED STATES
USA
FRANCE
FRANCE
UNITED STATES
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
GOUT
GUILLOT
HABIG
Lilian
Marie-Pierre
Michael
FRANCE
FRANCE
GERMANY
[email protected]
[email protected]
[email protected]
Teagasc
NIAB
Walloon Agricultural
Research Center
Curtin University
Bayer Cropscience NV
USDA Fargo, ND
Latvian Plant Protection
Research Centre Ltd.
Regional Field Crops
Research Center of Beja
Norwegian Institute for
Bioeconomy
Leibniz Institute for Natural
Product Research and
Infection Biology - HKI
RRES
DEPARTMENT OF
AGRICULTURE AND FOOD
WESTERN AUSTRALIA
Oregon State University
USDA-ARS
itk
INRA
USDA-Agricultural Research
Service
AgroParisTech
BIOGER
Christian-Albrechts
University of Kie
HAMZA-BEN YOUSSEF
Sonia Mihed
National institue of
agronomy of Tunisia (INAt)
TUNISIE
[email protected]
HANE
HARTMANN
HASSINE
HAUEISEN
James
Fanny
Marwa
Janine
Curtin University
ETH Zürich
AUSTRALIA
SWITZERLAND
TUNISIA
GERMANY
[email protected]
[email protected]
[email protected]
[email protected]
HAWKINS
HAWKINS
Nichola
Wayne
UNITED KINGDOM
UNITED STATES
[email protected]
[email protected]
HAYNES
HESS
Ken
Michael
UNITED KINGDOM
DEUTSCHLAND
[email protected]
[email protected]
HOLTGREWE STUKENBROCK
Eva
GERMANY
[email protected]
IORI
Angela
ITALY
[email protected]
JØRGENSEN
Lise Nistrup
DENMARK
[email protected]
KANYUKA
KARLSTEDT
KAY
KEMA
Konstantin
Frances
William
Gert H.j.
UNITED KINGDOM
GERMANY
UNITED KINGDOM
THE NETHERLANDS
[email protected]
[email protected]
[email protected]
[email protected]
KERDRAON
KETTLES
KING
KLEEMANN
KLITTICH
KOLLERS
KRAŠEVEC
Lydie
Graeme
Robert
Jochen
Carla
Sonja
Nada
FRANCE
UNITED KINGDOM
UNITED KINGDOM
GERMANY
UNITED STATES
GERMANY
SLOVENIA
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
Christian-Albrechts
University Kiel
Rothamsted Research
University of Arkansas,
Fayetteville
TUM School of Life Sciences
University of Kiel and Max
Planck Institute for
Evolutionary Biology
CREA - Consiglio per la
ricerca in agricoltura e
l'analisi dell'economia
agraria
Aarhus University Flakkebjerg
Rothamsted Research
Plant Research
International,Wageningen
University and Research
Centre, The Netherlands
INRA
Rothamsted Research
Rothamsted Research
Bayer
Dow AgroSciences
KWS LOCHOW GmbH
NATIONAL INSTITUTE OF
CHEMISTRY
KROJ
LE MIRE
Thomas
Géraldine
LEBRUN
LEE
LEMIRE
LILLEMO
Marc-Henri
Wing Sham
Geraldine
Morten
LIN
Min
MACCAFERRI
MADARIAGA
MASCHER
MATUSINSKY
MBOUP
MCDONALD
MCDONALD
Marco
Ricardo
Fabio
Pavel
Mamadou
Bruce
Megan
MEAD
Oliver
MEAMICHE NEDDAF
MEHRA
MEHRABI
Hayet
Lucky
Rahim
MEISSNER
MEJRI
MEULEWAETER
MILGATE
MILLYARD
MIRZADI GOHARI
MÖLLER
Ruth
Samara
Frank
Andrew
Linda
Amir
Mareike
OLIVER
OTHMENI
PALICOVÁ
PALMA GUERRERO
PITARCH
PRODI
RAY
Richard
Manel
Jana
Javier
Anaïs
Antonio
Rumiana
INRA
University of Liege Gembloux Agro Bio Tech
BIOGER
Rothamsted Research
Gembloux Univ
Norwegian University of Life
Sciences
Sciences
University of Bologna
INIA CHILE
Agroscope IPV
Agrotest fyto, ltd.
DuPont de Nemours
ETH Zurich
The Australian National
University
Australian National
University
Seed and Plant
Improvement Institute
Bayer CropScience AG
ISA Lille
Bayer Cropscience
NSW DPI
Durham University
Wageningen University
Christian-AlbrechtsUniversity Kiel
Curtin University
Crop Research institute
ETH Zurich
INRA BIOGER
University of Bologna
University of Nottingham
FRANCE
BELGIUM
[email protected]
[email protected]
FRANCE
UNITED KINGDOM
BELGIUM
NORWAY
[email protected]
[email protected]
[email protected]
[email protected]
NORWAY
[email protected]
ITALY
CHILE
SWITZERLAND
CZECH REPUBLIC
FRANCE
SWITZERLAND
AUSTRALIA
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
AUSTRALIA
[email protected]
ALGERIA
UNITED STATES
IRAN
[email protected]
[email protected]
[email protected]
GERMANY
FRANCE
BELGIUM
AUSTRALIA
ENGLAND
THE NETHERLANDS
GERMANY
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
AUSTRALIA
TUNISIA
CZECH REPUBLIC
SWITZERLAND
FRANCE
ITALIA
UNITED KINGDOM
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
REIGNAULT
Philippe
RIDENOUR
ROBERT
ROUXEL
RUDD
RUUD
John
Corinne
Thierry
Jason
Anja Karine
SADANANDOM
SAEED
SAINDRENAN
SAINTENAC
SANCHEZ VALLET
SEE
SGHYER
Ari
Khaldoon
Patrick
Cyrille
Andrea
Pao Theen
Hind
SHAW
SIAH
SIDHU
SINGH
Michael
Ali
Yaadwinder
Pawan
SOMAI-JEMMALI
SPERSCHNEIDER
STAHL
STUKENBROCK
SUFFERT
TABIB GHAFFARY
Lamia
Jana
Dietmar J
Eva
Frédéric
Seyed Mahmoud
TAN
TARANTO
Kar-Chun
Adam
THIERRY
THINES
Maud
Eckhard
Université du Littoral Côte
d'Opale
INRA
INRA
RRES
Sciences
Durham university
CNRS
INRA - Site de Crouel
ETH
Curtin University
Center of Life and Food
Sciences Weihenstephan,
Technische Universität
München
Universuity of Reading
ISA Lille
International Maize and
Wheat Improvement Center
(CIMMYT)
CSIRO Agriculture
KWS SAAT SE
CAU Kiel
INRA
Safiabad Agricultural
Research Center
Curtin University
The Australian National
University
INRA BIOGER
IBWF gGmbH / Johannes
Gutenberg-Universität Mainz
FRANCE
[email protected]
USA
FRANCE
FRANCE
UNITED KINGDOM
NORWAY
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
UNITED KINGDOM
UNITED KINGDOM
FRANCE
FRANCE
SWITZERLAND
AUSTRALIA
GERMANY
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
UK
FRANCE
UNITED KINGDOM
MEXICO
[email protected]
[email protected]
[email protected]
[email protected]
TUNISIA
AUSTRALIA
GERMANY
GERMANY
FRANCE
IRAN
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
AUSTRALIA
AUSTRALIA
[email protected]
[email protected]
FRANCE
GERMANY
[email protected]
[email protected]
THOMAS
THYNNE
Graham
Elisha
Australian National
University
University of Bristol
Syngenta Crop Protection
Münchwilen AG
UNITED KINGDOM
AUSTRALIA
[email protected]
[email protected]
TILEY
TORRIANI
Anna
Stefano
UNITED KINGDOM
SWITZERLAND
[email protected]
[email protected]
TRABELSI
VAGNDORF
Imen
Nana
INRAT
TUNISIA
Aarhus University, Denmark DENMARK
[email protected]
[email protected]
VALADE
Romain
Arvalis Institut du végétal
[email protected]
Vidal
TIPHAINE
[email protected]
WALCZEWSKI
Jakub
UMR INRA-AgroParisTech
FRANCE
EcoSys
Plant Breeding and
POLAND
Acclimatization Institue -NRI
WALKER
WELCH
WIECZOREK
WONNEBERGER
Anne Sophie
Thomas
Thies Marten
Ronja
FRANCE
IRELAND
DENMARK
NORWAY
[email protected]
[email protected]
[email protected]
[email protected]
YEMELIN
ZACCARON
ZHOU
Alexander
Marcio
Binbin
INRA
Aarhus University
Sciences
IBWF gGmbH
GERMANY
UNITED STATES
IRELAND
[email protected]
[email protected]
[email protected]
FRANCE
[email protected]

Untitled - 13th European Conference on Fungal Genetics

Transcription

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