Unravelling the cause of Black Pod Syndrome of narrow

Monica Kehoe
School of Plant Biology and The UWA Institute of Agriculture, Faculty of Science
Monica completed a Bachelor of Science with a major in
Microbiology at The University of Melbourne, and moved to
Western Australia in 2005 to work in Plant Virology at the
Department of Agriculture and Food WA (DAFWA).
Her fascination with (plant) viruses and her interest in research
led to an honours degree at Murdoch university, where she
worked on resistance phenotypes to Turnip mosaic virus in
mustard species.
She commenced her PhD at UWA in 2011, working on Black Pod
Syndrome in lupins. She continues to be based at DAFWA where
she has participated in a wide range of research projects,
including viruses in broadacre and agricultural crops.
The University of Western Australia
THE UWA INSTITUTE OF AGRICULTURE
Postgraduate Showcase 2013: Frontiers in Agriculture
Unravelling the cause of Black Pod Syndrome of narrow-leafed lupins
Monica Kehoe
The University of Western Australia
Acknowledgements
Supervisors: Roger Jones and Bevan Buirchell
DAFWA: Brenda Coutts, Stuart Vincent and Eva Gajda
GRDC for funding (GRDC supported PhD Project GRS10039)
The University of Western Australia
Australia grows 85% of global crop,
WA 80% of national crop
2005-2010 average area was
540,000 ha, av. yield 1.2 t/ha
Based on soils and climate, 1.6
million ha possible
Black Pod Syndrome major reason
yields below potential, especially
in south coast zone
Lupin production zones
The University of Western Australia
Pods, especially primaries,
turn black or dark brown
producing few or no seeds
Causes other than virus now
ruled out
Black Pod Syndrome (BPS)
BPS and late Bean yellow
mosaic virus (BYMV)
infection coincide
Differences between cultivar plots
The University of Western Australia
BYMV in narrow-leafed lupins
Early infection
Spread by aphids
Nearby pasture
Necrosis, shepherds crook,
death
Nbm-1 gene
Typical early season BYMV symptoms
The University of Western Australia
Serological (ELISA)
Molecular (PCR)
Green leaf
Necrotic stem
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Initial glasshouse studies reproduced BPS in plants inoculated with BYMV
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2011 survey
5 locations
Testing by ELISA and PCR
133 plants – 72 symptomatic
Typical BPS in the field
Multiple samples per plant - 314
Best spot to test = stem, below black pods
BPS symptomatic samples
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Number
ELISA
PCR
Section of plant
of
samples POTY BYMV POTY BYMV
Stem (near black
pods)
72
75%
83%
99%
82%
Stem (mid)
72
33%
61%
89%
58%
Leaf
48
2%
19%
96%
48%
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Reproducing BPS in the glasshouse
Mandelup vs Jenabillup
8 plants per cultivar inoculated every two weeks
Infection before flowering = typical BYMV symptoms:
Test
Test vs Control
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Infection at primary pod stage – black pod and plant death
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Infection after 1° pods fully developed and 2° and/or 3° pods formed
= typical BPS symptoms
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Drawback: it takes 6 months (and a whole glasshouse) to get here!
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Koch’s Postulates
Lupin BPS samples
positive for BYMV
BPS symptoms occur
BYMV inoculate
to other host
BYMV used to
infect healthy lupin
BYMV detected in
formerly healthy lupin
The University of Western Australia
THE UWA INSTITUTE OF AGRICULTURE
Postgraduate Showcase 2013: Frontiers in Agriculture
Summary
BYMV causes BPS
Time of infection critical for BPS symptoms
Is the Nbm-1 gene responsible?
Can closely related viruses cause BPS?
Solution?
The University of Western Australia