Three LysM effectors of Zymoseptoria tritici collectively disarm chitin-triggered plant immunity
Three LysM effectors of Zymoseptoria tritici collectively disarm chitin-triggered plant immunity
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小麦发酵斑孢菌的三个 LysM 效应子共同解除了几丁质触发的植物免疫
DOI：
10.1101/2020.06.24.169789
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Tian H
中科院分区：
文献类型：
--
作者：
Tian H
几丁质是真菌细胞壁的主要结构成分，充当微生物相关分子模式（MAMP），在被植物宿主识别后，触发免疫反应的激活。为了避免这些反应的激活，小麦的小麦壳针孢 (STB) 病原体小麦发酵壳孢 (Zymoseptoria tritici) 会分泌 LysM 效应蛋白。此前，LysM 效应子 Mg1LysM 和 Mg3LysM 已被证明可以保护真菌菌丝免受宿主几丁质酶的侵害。此外，Mg3LysM（而非 Mg1LysM）被证明可以抑制几丁质诱导的活性氧 (ROS) 产生。尽管最初第三个 LysM 效应基因被视为假定的假基因而被忽视，但我们现在提供功能数据来表明该基因还编码一个名为 Mgx1LysM 的 LysM 效应基因，该基因在小麦定殖期间发挥功能。而 Mg3LysM 对 Z 做出了主要贡献。 小麦毒力，Mgx1LysM 和 Mg1LysM 对 Z 做出贡献。 小麦毒力较小，影响较小。所有三个 LysM 效应器都显示出部分功能冗余。我们进一步证明 Mgx1LysM 结合几丁质，抑制几丁质诱导的 ROS 爆发，并能够保护真菌菌丝免受几丁质酶水解。最后，我们证明 Mgx1LysM 能够进行几丁质诱导的聚合。总的来说，我们的数据表明 Z. tritici 利用三个 LysM 效应子来解除几丁质触发的小麦免疫力。
Chitin is a major structural component of fungal cell walls and acts as a microbe‐associated molecular pattern (MAMP) that, on recognition by a plant host, triggers the activation of immune responses. To avoid the activation of these responses, the Septoria tritici blotch (STB) pathogen of wheat,Zymoseptoria tritici, secretes LysM effector proteins. Previously, the LysM effectors Mg1LysM and Mg3LysM were shown to protect fungal hyphae against host chitinases. Furthermore, Mg3LysM, but not Mg1LysM, was shown to suppress chitin‐induced reactive oxygen species (ROS) production. Whereas initially a third LysM effector gene was disregarded as a presumed pseudogene, we now provide functional data to show that this gene also encodes a LysM effector, named Mgx1LysM, that is functional during wheat colonization. While Mg3LysM confers a major contribution toZ. triticivirulence, Mgx1LysM and Mg1LysM contribute toZ. triticivirulence with smaller effects. All three LysM effectors display partial functional redundancy. We furthermore demonstrate that Mgx1LysM binds chitin, suppresses the chitin‐induced ROS burst, and is able to protect fungal hyphae against chitinase hydrolysis. Finally, we demonstrate that Mgx1LysM is able to undergo chitin‐induced polymerization. Collectively, our data show thatZ. triticiutilizes three LysM effectors to disarm chitin‐triggered wheat immunity.