Research Accomplishment Reports 2011

Dissecting Defense Signaling Pathways in Soybean and Arabidopsis

A. Kachroo
Department of Plant Pathology

 

Non-Technical Summary

Despite the economic importance of the soybean crop and the devastating losses incurred by its diseases very little is known about the molecular mechanisms underlying host defense against pathogens infecting soybean. The purpose of this study is to understand the molecular mechanisms governing soybean defense against two of its major pathogens, Phtophthtora sojae and soybean mosiac virus.

2011 Project Description

Research pertaining to both objective 1 and 2 was conducted.

Components mediating cross talk between oleic acid, salicylic acid and jasmonic acid pathways were identified.

Components of resistance protein-derived signaling pathways were identified from soybean and Arabidopsis.

A key mobile inducer of systemic immunity was identified.

Research findings were presented as five-oral and two-poster presentations at society (American Phytopathological Society, American Society of Plant Biologists, American Society for Virology) annual conferences (2011).

Two undergraduate and two graduate students, one visiting scholar, and four postdoctoral researchers received scientific training pertaining to this work.

2011 Impact

Showed that some components of the salicylic acid signaling pathway exist as a complex and influence their own intracellular localization during resistance signaling.

Identified glycerol-3-phosphate as a key component of the mobile signal required for inducing systemic acquired resistance in diverse plants.

Demonstrated the efficacy of the bean pod mottle virus-based vector for silencing and overexpression in common bean.

Showed that the downregulation of genes encoding w3-fatty acid destaurase in soybean increases seed size.

Identified jasmonic acid as a key modulator of soybean defense to bean pod mottle virus.

Showed that WRKY transcription factors mediate the low oleic acid- and salicylic acid-derived repression of jasmonic acid-dependent defense responses in Arabidopsis.

2011 Publications

Zhu S, Jeong R-D, Venugopal SC, Navarre DA, Kachroo A, Kachroo, P (2011) SAG101 forms a ternary complex with EDS1 and PAD4 and is required for resistance signaling against turnip crinkle virus. PLoS Pathogens 7:e1002318

Mandal MK, Chanda B, Xia Y, Yu K, Sekine K, Gao Q-M, Selote D, Kachroo A Kachroo P. (2011) Glycerol-3-phosphate and systemic immunity. Plant Signaling & Behavior 6:11

Diaz C, Annamalai P, Sanchez F, Kachroo A, Ghabrial SA (2011) An effective virus-based gene silencing method for functional genomics studies in common bean. Plant Methods 7:1-11

Chanda B, Xia Y, Mandal MK, Yu K, Sekine KT, Gao QM, Selote D, Hu Y, Stromberg A, Navarre D, Kachroo A, Kachroo P (2011) Glycerol-3-phosphate is a critical mobile inducer of systemic immunity in plants. Nature Genetics 43:421-427 (Highlighted in Science Daily: http://www.sciencedaily.com/releases/2011/03/110328101609 .htm; Article reviewed by Faculty of 1000)

Singh A, El-Habbak M, Fu D-Q, Ghabrial SA, Kachroo A (2011) Silencing genes encoding omega-3 fatty acid desaturase alters seed size and accumulation of Bean pod mottle virus in soybean. Molecular Plant-Microbe Interactions 24:506-515 (Research highlighted in the fall 2010 issue of The Soybean Sentinel, a Kentucky Soybean Association magazine)

Gao Q-M, Venugopal SC, Navarre DA, Kachroo A (2011) Low oleic acid-derived repression of jasmonic acid-inducible defense responses requires the WRKY50 and WRKY51 proteins. Plant Physiology 155:464-476