小柯机器人

近日，德国科隆大学柴继杰等研究人员合作发现，一个小麦抗病小体定义免疫受体通道的共同原则。相关论文于2022年9月26日在线发表于国际学术期刊《自然》。

研究人员表示，植物细胞内核苷酸结合的富含亮氨酸的重复受体（NLR）检测病原体效应物来触发免疫反应。双子叶植物拟南芥的含有螺旋线圈结构域的NLR（CNL）ZAR1间接识别病原体效应物，进而诱导形成一个大型异构体蛋白复合物，称为ZAR1抵抗体，其功能是ZAR1介导的免疫所需的钙通道。抗病小体和通道的活动在植物CNL中是否保守仍是未知的。

研究人员报告了小麦CNL Sr355与小麦茎锈病病原体的效应物AvrSr356复合的冷冻电镜结构。效应物与Sr35的富含亮氨酸重复序列直接结合，形成一个五聚体Sr35-AvrSr35复合物，被称之为Sr35抗病小体。小麦Sr35和拟南芥ZAR1抗病小体具有惊人的结构相似性，包括富含白蛋白的重复结构域中的一个精氨酸簇，该簇以前没有被确认为保守的，它与盘绕结构域中的“EDVID”模体共同出现并形成分子内相互作用。电生理测量表明，Sr35抗病小体表现出非选择性的阳离子通道活性。这些结构上的见解使研究人员能够产生识别AvrSr35的密切相关的小麦和大麦孤儿NLR的新变体。这些数据支持植物中CNL抗病小体的演化保守性，并证明了基于结构的NLR工程化可用于作物改良的原则。

附：英文原文

Title: A wheat resistosome defines common principles of immune receptor channels

Author: Frderer, Alexander, Li, Ertong, Lawson, Aaron W., Deng, Ya-nan, Sun, Yue, Logemann, Elke, Zhang, Xiaoxiao, Wen, Jie, Han, Zhifu, Chang, Junbiao, Chen, Yuhang, Schulze-Lefert, Paul, Chai, Jijie

Issue&Volume: 2022-09-26

Abstract: Plant intracellular nucleotide-binding leucine-rich repeat receptors (NLRs) detect pathogen effectors to trigger immune responses1. Indirect recognition of a pathogen effector by the dicotyledonous Arabidopsis thaliana coiled-coil domain containing NLR (CNL) ZAR1 induces the formation of a large hetero-oligomeric protein complex, termed the ZAR1 resistosome, which functions as a calcium channel required for ZAR1-mediated immunity2,3,4. Whether the resistosome and channel activities are conserved among plant CNLs remains unknown. Here we report the cryo-electron microscopy structure of the wheat CNL Sr355 in complex with the effector AvrSr356 of the wheat stem rust pathogen. Direct effector binding to the leucine-rich repeats of Sr35 results in the formation of a pentameric Sr35–AvrSr35 complex, which we term the Sr35 resistosome. Wheat Sr35 and Arabidopsis ZAR1 resistosomes bear striking structural similarities, including an arginine cluster in the leucine-rich repeats domain not previously recognized as conserved, which co-occurs and forms intramolecular interactions with the 'EDVID' motif in the coiled-coil domain. Electrophysiological measurements show that the Sr35 resistosome exhibits non-selective cation channel activity. These structural insights allowed us to generate new variants of closely related wheat and barley orphan NLRs that recognize AvrSr35. Our data support the evolutionary conservation of CNL resistosomes in plants and demonstrate proof of principle for structure-based engineering of NLRs for crop improvement.

DOI: 10.1038/s41586-022-05231-w

Source: https://www.nature.com/articles/s41586-022-05231-w

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