Phytophthora infestansRXLR effector PITG20303 targets a potato MKK1 protein to suppress plant immunity
Phytophthora infestansRXLR effector PITG20303 targets a potato MKK1 protein to suppress plant immunity
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致病疫霉 RXLR 效应子 PITG20303 靶向马铃薯 MKK1 蛋白以抑制植物免疫
DOI：
10.1111/nph.16861
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发表时间：
2020-09-12
期刊：
影响因子：
9.4
通讯作者：
Shan, Weixing
中科院分区：
文献类型：
--
作者：
Du, Yu;Chen, Xiaokang;Shan, Weixing
病原体分泌大量的效应子进入宿主细胞以调节植物免疫。分析效应子在改变其宿主靶蛋白功能中的作用将揭示植物免疫系统的关键组成部分。在这里，我们表明致病疫霉RXLR效应子PITG 20303，AVRblb 2（PITG 20300）的毒性变体，其逃避抗性蛋白Rpi-blb 2的识别，抑制PAMP触发的免疫（PTI），并通过靶向和稳定马铃薯MAPK级联蛋白StMKK 1来促进病原体定殖。PITG 20300和PITG 20303都靶向StMKK 1，这一点通过多次体内和体外试验证实，并且StMKK 1被证明是植物免疫的负调节剂，这一点通过过表达和基因沉默来确定。StMKK 1是植物PTI的负调控因子，其激酶活性是其抑制PTI和与效应子相互作用所必需的。PITG 20303部分依赖于MKK 1，PITG 20300不依赖于MKK 1来抑制PTI诱导的活性氧簇爆发，而核靶向的PITG 20303和PITG 20300的全部毒力活性依赖于MKK 1。我们的研究结果表明，PITG 20303和PITG 20300的目标和稳定的植物MAPK级联信号蛋白StMKK 1负调控植物PTI的反应。
Pathogens secret a plethora of effectors into the host cell to modulate plant immunity. Analysing the role of effectors in altering the function of their host target proteins will reveal critical components of the plant immune system. Here we show thatPhytophthora infestansRXLR effector PITG20303, a virulent variant of AVRblb2 (PITG20300) that escapes recognition by the resistance protein Rpi-blb2, suppresses PAMP-triggered immunity (PTI) and promotes pathogen colonization by targeting and stabilizing a potato MAPK cascade protein, StMKK1. Both PITG20300 and PITG20303 target StMKK1, as confirmed by multiplein vivoandin vitroassays, andStMKK1was shown to be a negative regulator of plant immunity, as determined by overexpression and gene silencing. StMKK1is a negative regulator of plant PTI, and the kinase activities of StMKK1 are required for its suppression of PTI and effector interaction. PITG20303 depends partially on MKK1, PITG20300 does not depend on MKK1 for suppression of PTI-induced reactive oxygen species burst, while the full virulence activities of nuclear targeted PITG20303 and PITG20300 are dependent on MKK1. Our results show that PITG20303 and PITG20300 target and stabilize the plant MAPK cascade signalling protein StMKK1 to negatively regulate plant PTI response.