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Poster: Molecular & Cellular Plant-Microbe Interactions: Plant Defense Responses


The Role of Ethylene in PAMP-Triggered Immunity in Fusarium Crown Rot (FCR) Disease Resistance in Wheat
S. ALLEN (1), X. Xiao (1), K. Bhide (1), S. Scofield (2) (1) Purdue University, U.S.A.; (2) USDA-ARS, Purdue University, U.S.A.

Fusarium Crown Rot (FCR) is a devastating cereal crop disease cause by necrotrophic fungal pathogens Fusarium graminearum and Fusarium pseudograminearum. Plants detect conserved pathogen-associated molecular patterns (PAMPs) through pattern-recognition receptors. Then, a signal cascade is triggered resulting in PAMP-Triggered Immunity (PTI) response such as expression of defense response genes and production of plant hormones jasmonic acid, salicylic acid, and ethylene. A model proposed by Zipfel in 2013 suggests that ethylene functions to prime additional signaling pathways for sustained PTI response. Our laboratory has shown that disease resistance to FCR can be enhanced in susceptible wheat cultivars by stimulating the ethylene-signaling pathway with ethylene biosynthetic precursor 1-aminocyclopropene-1carboxylic acid (ACC). Additionally, resistant cultivars become more susceptible when ethylene-signaling is inhibited by treatment with the competitive inhibitor 1-methylcylopropene (1-MCP). RNA-Seq analysis of FCR-susceptible wheat cv ‘Kennedy’ in response to ACC or 1-MCP application and F.graminearum inoculation demonstrates significant difference in Differentially Expressed Genes (DEGs) within several disease-response categories such as peroxidases, pathogenesis-related proteins, and WRKY transcription factors. Currently, we are examining the transcriptome of FCR-resistant cv ‘Bobwhite’ to identify additional candidate genes involved in FCR resistance.