suppression of plant resistance gene-based immunity by a fungal effector由真菌抑制植物抗性基因免疫效应.pdf

Suppression of Plant Resistance Gene-Based Immunity by a Fungal Effector Petra M. Houterman, Ben J. C. Cornelissen, Martijn Rep* Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands Abstract The innate immune system of plants consists of two layers. The first layer, called basal resistance, governs recognition of conserved microbial molecules and fends off most attempted invasions. The second layer is based on Resistance (R) genes that mediate recognition of effectors, proteins secreted by pathogens to suppress or evade basal resistance. Here, we show that a plant-pathogenic fungus secretes an effector that can both trigger and suppress R gene-based immunity. This effector, Avr1, is secreted by the xylem-invading fungus Fusarium oxysporum f.sp. lycopersici (Fol) and triggers disease resistance when the host plant, tomato, carries a matching R gene (I or I-1). At the same time, Avr1 suppresses the protective effect of two other R genes, I-2 and I-3. Based on these observations, we tentatively reconstruct the evolutionary arms race that has taken place between tomato R genes and effectors of Fol. This molecular analysis has revealed a hitherto unpredicted strategy for durable disease control based on resistance gene combinations. Citation: Houterman PM, Cornelissen BJC, Rep M (2008) Suppression of Plant Resistance Gene-Based Immunity by a Fungal Effector. PLoS Pathog 4(5): e1000061. doi:10.1371/journal.ppat.1000061 Editor: Brendan P. Cormack, Johns Hopkins University School of Medicine, United States of America Received November 26, 2007; Accepted April 9, 2008; Published May 9, 2008 Copyright: 2008 Houterman et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, an