Poster: Plant Pathogen/Symbiont Interactions

Abs # 728: Genetic analysis of pathogen-induced WRKY gene expression in Arabidopsis

Presenter:	Chen, Zhixiang , zhixiang@purdue.edu
Authors	Chen, Zhixiang  (A)   Fan, Baofang  (A)
Affiliations:	(A): Purdue University

Transcriptional regulation of plant host gene expression is a central part of plant defense responses and elucidating the molecular mechanisms of the signaling pathways leading to differential expression of plant host genes holds the key to the understanding of the molecular basis of plant disease resistance. Over the last several years, we have been studying a group of plant transcription factors containing the novel WRKY DNA-binding domains and their possible involvement in plant disease resistance. A number of reported studies strongly suggest that plant WRKY proteins play important roles in plant defense responses through regulation of plant host gene expression. Interestingly, many WRKY genes themselves are transcriptionally activated in plants upon pathogen infection. To identify early signaling components in the induction of plant WRKY gene expression, we have attempted to isolate Arabidopsis mutants that are defective in pathogen-induced WRKY gene expression. Using a GUS reporter gene driven by the Arabidopsis AtWRKY18 gene promoter, we have screened a population of chemically mutagenized Arabidopsis plants and identified a number of putative non-WRKY expression mutants. Preliminary studies indicated that these mutants were also defective in the inducible expression of other WRKY genes and were extremely susceptible to the bacterial pathogen Pseudomonas syringae. Further analysis of these mutants and cloning of the mutant genes will provide new insights into the signaling pathways of plant defense responses.