Department of Molecular Genetics and Cell Biology; The University of Chicago; Chicago, IL USA.
Plant Signal Behav. 2012 Sep 1;7(9):1129-31. doi: 10.4161/psb.21319. Epub 2012 Aug 17.
Type III secreted effectors shape the potential of bacterial pathogens to cause disease on plants. Some effectors affect pathogen growth only in specific niches. For example, HopZ3 causes reduced epiphytic growth of Pseudomonas syringae strain B728a on Nicotiana benthamiana. This raises the question of whether genes important for effector-triggered disease resistance are needed for responses to effectors whose major effect is in the epiphytic niche. We report that SGT1b, a protein known to be important for defense activation, is essential for HopZ3-mediated suppression of PsyB728a epiphytic growth. SGT1b is required for HopZ3- and AvrB3-induced cell death in N. benthamiana plants that express the Pto resistance gene from tomato. We suggest that HopZ3 activates R gene mediated responses in N. benthamiana.
III 型分泌效应子决定了细菌病原体在植物上致病的潜力。一些效应子仅在特定小生境中影响病原体的生长。例如，HopZ3 导致 Pseudomonas syringae 菌株 B728a 在 Nicotiana benthamiana 上的附生生长减少。这就提出了一个问题，即对于主要在附生小生境中起作用的效应子，是否需要对效应子触发的疾病抗性至关重要的基因。我们报告说，SGT1b 是一种已知对防御激活很重要的蛋白质，对于 HopZ3 介导的 PsyB728a 附生生长抑制是必需的。在表达来自番茄的 Pto 抗性基因的 N. benthamiana 植物中，SGT1b 是 HopZ3 和 AvrB3 诱导细胞死亡所必需的。我们认为 HopZ3 在 N. benthamiana 中激活 R 基因介导的反应。
