植物免疫受体蛋白如何精准感知病原物入侵是植物启动免疫系统的关键环节，本项目前期工作发现番茄抗病蛋白Sw-5b N-末端1-194位氨基酸区域（NTD1）与GTPase核苷酸交换因子（GEF）具有氨基酸序列和三维结构上的同源性，结合当前植物免疫受体识别病原物效应蛋白的前沿进展，我们推测番茄斑萎病毒是否劫持植物中的GEF寄主因子来促进病毒的侵染？而Sw-5b为了对抗病毒的侵染则进化出一个GEF同源结构域作为诱饵蛋白来监测病毒的入侵，进而启动免疫反应。本项目拟筛选与番茄斑萎病毒移动蛋白NSm互作的GEF类寄主因子，并探明其在病毒侵染过程中的作用，揭示番茄斑萎病毒通过劫持GEF寄主因子的致病机制；同时解析Sw-5b NTD1与NSm的互作关系及结构基础，进一步探明Sw-5b NTD1的生化特性及功能，揭示Sw-5b通过整合与寄主因子同源结构域作为诱饵蛋白监测病毒入侵的新机制。

Plant intracellular nucleotide-binding leucine-rich repeat (NLR) immune receptors play critical roles in pathogen surveillance. The recognition of pathogen-derived effectors by immune receptors is critical for the activation of plant immune responses. Based on the previous study that the Sw-5b NTD1 (1-194aa) shared amino acid sequence identity and structure similarity with guanine exchange factor (GEF), we propose that TSWV may highjack GEF host factor to promote the infection, and Sw-5b evolved a GEF-like domain as bait to recognize the TSWV NSm protein. Thus, this project aims to understand how Sw-5b recognises the movement protein NSm of tospovirus in molecular detail. Two main research lines are pursued in this project. First, we focus on the identification of compatibility/susceptibility genes by screening for host protein targets that are manipulated by virus effector NSm. The second line is the interaction between Sw-5b NTD1 domain and TSWV NSm. We plan to purify the Sw-5b NTD1/NSm complex protein and solve the crystal structure. The results are expected to reveal the decoy mechanism of tomato immune receptor protein Sw-5b recognizing tomato spotted wilt virus, and expand our understanding on the role of non-canonical domain of plant NLRs in pathogen recognition and defense.