Grant Sarah R, Fisher Emily J, Chang Jeff H, Mole Beth M, Dangl Jeffery L
Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
Annu Rev Microbiol. 2006;60:425-49. doi: 10.1146/annurev.micro.60.080805.142251.
Diverse gram-negative bacteria deliver effector proteins into the cells of their eukaryotic hosts using the type III secretion system. Collectively, these type III effector proteins function to optimize the host cell environment for bacterial growth. Type III effector proteins are essential for the virulence of Pseudomonas syringae, Xanthomonas spp., Ralstonia solanacearum and Erwinia species. Type III secretion systems are also found in nonpathogenic pseudomonads and in species of symbiotic nitrogen-fixing Rhizobium. We discuss the functions of type III effector proteins of plant-associated bacteria, with an emphasis on pathogens. Plant pathogens tend to carry diverse collections of type III effectors that likely share overlapping functions. Several effectors inhibit host defense responses. The eukaryotic host targets of only a few type III effector proteins are currently known. We also discuss possible mechanisms for diversification of the suite of type III effector proteins carried by a given bacterial strain.
多种革兰氏阴性菌利用Ⅲ型分泌系统将效应蛋白输送到其真核宿主细胞中。这些Ⅲ型效应蛋白共同作用，优化宿主细胞环境以利于细菌生长。Ⅲ型效应蛋白对于丁香假单胞菌、黄单胞菌属、青枯雷尔氏菌和欧文氏菌属的致病性至关重要。Ⅲ型分泌系统也存在于非致病性假单胞菌以及共生固氮根瘤菌属的物种中。我们讨论了植物相关细菌Ⅲ型效应蛋白的功能，重点是病原体。植物病原体往往携带多种Ⅲ型效应子，它们可能具有重叠的功能。一些效应子会抑制宿主的防御反应。目前仅知道少数几种Ⅲ型效应蛋白的真核宿主靶点。我们还讨论了给定细菌菌株所携带的Ⅲ型效应蛋白组多样化的可能机制。
