Smart Farm Research Center, Korea Institute of Science and Technology, Gangneung, Gangwon-do, 25451, South Korea.
Vegetable Research Division, Rural Development Administration, National Institute of Horticulture and Herbal Science, Wanju, 55365, South Korea.
Genes Genomics. 2019 May;41(5):499-506. doi: 10.1007/s13258-019-00801-1. Epub 2019 Mar 4.
Innate immune signaling of plants is initiated by pattern recognition receptors (PRRs) at the plasma membrane. Upon pathogen attack, PRRs recognize pathogen-associated molecular patterns (PAMPs) via ectodomain and lead to signaling cascade via cytoplasmic kinase domain. PAMP-triggered immunity (PTI) activates basal defense responses sufficient to confer broad-spectrum disease resistance by inhibiting pathogen entry and growth. On the other hand, one of the major virulence factors in plant-pathogenic bacteria is type III secretion system, which can deliver effector proteins into the host cell and modulate host cellular processes. Most type III effectors are implicated in PTI suppression, and PRRs have been identified as targets of multiple type III effectors. Mutants defective in T3SS lack pathogenicity in many bacterial species, revealing that T3SS-mediated PTI suppression is critical for host colonization and subsequent disease development. This review summarizes molecular basis of bacterial pathogen perception by plant PRRs and also interaction between PRRs and type III effectors during early stages of plant-pathogen interaction.
植物的先天免疫信号是由质膜上的模式识别受体（PRRs）启动的。在病原体攻击时，PRRs 通过胞外结构域识别病原体相关分子模式（PAMPs），并通过细胞质激酶结构域引发信号级联反应。病原体触发的免疫（PTI）通过抑制病原体进入和生长来激活基本防御反应，从而赋予广谱的疾病抗性。另一方面，植物病原细菌的主要毒力因子之一是 III 型分泌系统，它可以将效应蛋白输送到宿主细胞中，并调节宿主细胞的过程。大多数 III 型效应蛋白都参与了 PTI 的抑制，PRRs 已被鉴定为多种 III 型效应蛋白的靶标。T3SS 缺陷突变体在许多细菌物种中缺乏致病性，这表明 T3SS 介导的 PTI 抑制对于宿主定植和随后的疾病发展至关重要。本综述总结了植物 PRRs 对细菌病原体的感知的分子基础，以及 PRRs 和 III 型效应蛋白在植物-病原体相互作用早期阶段的相互作用。
