Research Accomplishment Reports 2010

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.

2010 Project Description

Results related to the roles of the phytohormones salicylic acid and jasmonic acid in soybean defense to microbial pathogens were obtained. Several signaling components of the soybean and Arabidopsis defense signaling pathways were also identified.

Research findings were presented as three-oral and five-poster presentations at annual society (American Phytopathological Society, American Society of Plant Biologists, American Society for Virology) annual conferences (2010).

Three undergraduate and two graduate students, and three postdoctoral researchers received scientific training pertaining to this work.

2010 Impact

Identified soybean proteins that interact with bacterial avirulence effectors and demonstrated their roles in resistance protein-derived signaling.

Identified molecular components mediating soybean defense to the oomycete pathogen Phytophthora sojae.

Identified a gene whose downregulation increase seed size in soybean.

Showed that increased endogenous levels of jasmonic acid results in enhanced susceptibility to bean pod mottle virus (BPMV) in soybean. Jasmonic acid was thus identified as a key modulator of plant defense to BPMV.

Showed that low oleic acid-derived repression of jasmonic acid-dependent defense responses is mediated by two WRKY transcription factors in Arabidopsis. These proteins also mediate plant defense to the fungal pathogen Botrytis cinerea.

Showed that light and components required for light perception are intricately involved in plant defense to viruses.

Showed that the plant cuticle plays an important role in mediating systemic immunity and that gibberillic acid contributes to proper cuticle development and thereby systemic immunity in plants.

2010 Publications

Singh A, El-Habbak M, Fu D-Q, Ghabrial SA, Kachroo A (2010) Omega-3 fatty acid desaturases regulate seed size and defense to bean pod mottle virus in soybean. Molecular Plant-Microbe Interactions (In press)

Gao Q-M, Venugopal SC, Navarre DA, Kachroo A (2010) WRKY50 and WRKY51 mediate low 18:1-derived repression of jasmonic acid-dependent defense responses. Plant Physiology (In press)

Xia Y, Yu K, Navarre DA, Seebold K, Kachroo A, Kachroo P. (2010) The glabra1 mutation affects cuticle formation and plant responses to microbes. Plant Physiology 154:833-846

Selote D, Kachroo A (2010) Structurally conserved RIN4-like proteins mediate pathogen effector perception in diverse plants. Plant Signaling and Behavior Vol. 5 issue 11 (http://www.landesbioscience.com/journals/psb/article/13462/)

Selote D, Kachroo A (2010) RPG1-B derived resistance to AvrB expressing Pseudomonas syringae requires RIN4-like proteins in soybean. Plant Physiology 153:1199-1211

Jeong R-D, Kachroo A, Kachroo P. (2010) Blue light photoreceptors are required for the stability and function of a resistance protein mediating viral defense in Arabidopsis. Plant Signaling and Behavior Vol 5 issue 11 (http://www.landesbioscience.com/journals/psb/article/13705/)

Jeong R-D, Chandra-Shekara AC, Barman SR, Navarre DA, Klessig D, Kachroo A, Kachroo P (2010) CRYPTOCHROME 2 and PHOTOTROPIN 2 regulate resistance protein mediated viral defense by negatively regulating a E3 ubiquitin ligase. Proceedings of the National Academy of Sciences USA 107:13538-13543 (This article was highlighted in the Faculty of 1000 Reviews)