A Xanthomonas uridine 5′-monophosphate transferase inhibits plant immune kinases
A Xanthomonas uridine 5′-monophosphate transferase inhibits plant immune kinases
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DOI：
10.1038/nature10962
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发表时间：
2012-05-03
期刊：
影响因子：
64.8
通讯作者：
Zhou, Jian-Min
中科院分区：
文献类型：
--
作者：
Feng, Feng;Yang, Fan;Zhou, Jian-Min
植物先天免疫在检测到细胞表面的病原体相关分子模式（PAMP）或植物细胞内的病原体效应蛋白时被激活（1-4）。PAMP触发的免疫和效应子触发的免疫共同构成了对各种植物病原体的强大防御。病原菌将多种效应蛋白注入宿主细胞以协助感染或繁殖。许多效应蛋白已显示出抑制植物免疫（5），但这些效应蛋白中的绝大多数的生物化学基础仍然未知。在这里，我们表明野油菜黄单胞菌致病变种野油菜III型效应子AvrAC通过特异性靶向拟南芥BIK 1和RIPK（已知介导免疫信号传导的两种受体样细胞质激酶）来增强毒力并抑制植物免疫（6-8）。AvrAC是一种尿苷酰转移酶，其将尿苷5 '-单磷酸添加到BIK 1和RIPK的活化环中并隐藏其中的保守磷酸化位点，从而降低其激酶活性并因此抑制下游信号传导。
Plant innate immunity is activated on the detection of pathogen-associated molecular patterns (PAMPs) at the cell surface, or of pathogen effector proteins inside the plant cell(1-4). Together, PAMP-triggered immunity and effector-triggered immunity constitute powerful defences against various phytopathogens. Pathogenic bacteria inject a variety of effector proteins into the host cell to assist infection or propagation. A number of effector proteins have been shown to inhibit plant immunity(5), but the biochemical basis remains unknown for the vast majority of these effectors. Here we show that the Xanthomonas campestris pathovar campestris type III effector AvrAC enhances virulence and inhibits plant immunity by specifically targeting Arabidopsis BIK1 and RIPK, two receptor-like cytoplasmic kinases known to mediate immune signalling(6-8). AvrAC is a uridylyl transferase that adds uridine 5'-monophosphate to and conceals conserved phosphorylation sites in the activation loop of BIK1 and RIPK, reducing their kinase activity and consequently inhibiting downstream signalling.