美国加州大学伯克利分校Brian J. Staskawicz、Eva Nogales等研究人员，合作解析出活化ROQ1抗病小体直接识别病原体效应蛋白XopQ的结构。这一研究成果于2020年12月4日发表在国际学术期刊《科学》上。

研究人员描述了活化ROQ1（识别黄单胞菌外蛋白Q，XopQ ）的3.8埃分辨率冷冻电镜结构，即本氏烟草（Nicotiana benthamiana）的核苷酸结合亮氨酸富集重复的受体（NLR）的Toll样白介素1受体（TIR）域与病原菌Xanthomonas euvesicatoria效应蛋白的结合。ROQ1直接与XopQ的预测活性位点和表面残基结合，同时形成四聚体抗病小体(resistosome)，这将TIR域聚集在一起以进行下游免疫信号传导。

这些结果提出了一种机制，可通过NLR直接识别效应蛋白，从而导致植物抗病小体的寡聚依赖性激活以及通过TIR域的信号传导。

据悉，动植物使用细胞内NLR来检测病原体感染，这些受体直接或间接识别病原体效应物并激活免疫应答。效应蛋白感知如何触发NLR激活仍然知之甚少。

附：英文原文

Title: Structure of the activated ROQ1 resistosome directly recognizing the pathogen effector XopQ

Author: Raoul Martin, Tiancong Qi, Haibo Zhang, Furong Liu, Miles King, Claire Toth, Eva Nogales, Brian J. Staskawicz

Issue&Volume: 2020/12/04

Abstract: Plants and animals detect pathogen infection using intracellular nucleotide-binding leucine-rich repeat receptors (NLRs) that directly or indirectly recognize pathogen effectors and activate an immune response. How effector sensing triggers NLR activation remains poorly understood. Here we describe the 3.8-angstrom-resolution cryo–electron microscopy structure of the activated ROQ1 (recognition of XopQ 1), an NLR native to Nicotiana benthamiana with a Toll-like interleukin-1 receptor (TIR) domain bound to the Xanthomonas euvesicatoria effector XopQ (Xanthomonas outer protein Q). ROQ1 directly binds to both the predicted active site and surface residues of XopQ while forming a tetrameric resistosome that brings together the TIR domains for downstream immune signaling. Our results suggest a mechanism for the direct recognition of effectors by NLRs leading to the oligomerization-dependent activation of a plant resistosome and signaling by the TIR domain.

DOI: 10.1126/science.abd9993

Source: https://science.sciencemag.org/content/370/6521/eabd9993