Kim Min Gab, da Cunha Luis, McFall Aidan J, Belkhadir Youssef, DebRoy Sruti, Dangl Jeffrey L, Mackey David
Department of Plant Cellular and Molecular Biology, Program in Molecular Cellular and Developmental Biology, The Ohio State University, Columbus, Ohio 43210, USA.
Cell. 2005 Jun 3;121(5):749-59. doi: 10.1016/j.cell.2005.03.025.
Plant cells have two defense systems that detect bacterial pathogens. One is a basal defense system that recognizes complex pathogen-associated molecular patterns (PAMPs). A second system uses disease-resistance (R) proteins to recognize type lll effector proteins that are delivered into the plant cell by the pathogen's type III secretion system. Here we show that these two pathways are linked. We find that two Pseudomonas syringae type III effectors, AvrRpt2 and AvrRpm1, inhibit PAMP-induced signaling and thus compromise the host's basal defense system. RIN4 is an Arabidopsis protein targeted by AvrRpt2 and AvrRpm1 for degradation and phosphorylation, respectively. We find that RIN4 is itself a regulator of PAMP signaling. The R proteins, RPS2 and RPM1, sense type III effector-induced perturbations of RIN4. Thus, R proteins guard the plant against type III effectors that inhibit PAMP signaling and provide a mechanistic link between the two plant defense systems.
植物细胞有两种检测细菌病原体的防御系统。一种是基础防御系统，可识别复杂的病原体相关分子模式（PAMPs）。第二种系统利用抗病（R）蛋白来识别III型效应蛋白，这些效应蛋白由病原体的III型分泌系统传递到植物细胞中。在此我们表明这两条途径是相互关联的。我们发现两种丁香假单胞菌III型效应蛋白AvrRpt2和AvrRpm1可抑制PAMP诱导的信号传导，从而损害宿主的基础防御系统。RIN4是一种拟南芥蛋白，分别被AvrRpt2和AvrRpm1靶向降解和磷酸化。我们发现RIN4本身就是PAMP信号传导的调节因子。R蛋白RPS2和RPM1可感知III型效应蛋白诱导的RIN4扰动。因此，R蛋白保护植物免受抑制PAMP信号传导的III型效应蛋白的侵害，并在植物的两种防御系统之间提供了一种机制联系。
