Functional characterization of Phytophthora infestans RXLR effector AVR2

Abstract

The P. infestans RXLR effector AVR2 interacts with BSU1-like phosphatases, which are known to positive regulators of Brassinosteroid signaling. I have used a combination of biochemical, molecular biology and reverse genetic approaches to characterize the function of AVR2 in host N. benthamiana and non-host A. thaliana.The expression of AVR2 in Arabidopsis leads to dwarf phenotype and abnormal stomata density. This phenotype is consistent with a defect in brassinosteroid signaling pathway. However, the transcriptome change analysis and activation studies of key brassinosteroid transcription factor BES1 showed except stomata biogenesis no deregulation by AVR2. AVR2 did not interfere with MAMP induced immune signaling responses: oxidative burst, MAPK activation expression of MIT-induced marker genes in Arabidopsis and N. benthamiana. However AVR2 interfered with programmed cell death in N. benthamiana and caused higher susceptibility to biotrophic pathogens P. syringae and P. capsici and increased resistance to necrotrophic A. brassicicola.