凝集素蛋白OsMBL1在几丁质介导的水稻免疫反应中的作用机制研究

几丁质触发的植物免疫是水稻重要的基础抗性反应，其抗病信号网络的解析是水稻抗病机理研究的热点。我们前期的研究发现，几丁质酶MoChi1作为效应因子通过竞争和降解几丁质参与稻瘟病菌的致病性，而水稻凝集素蛋白OsMBL1则与MoChi1互作并竞争结合几丁质，来诱发水稻的基础免疫反应。但作为一种新的几丁质受体蛋白，OsMBL1识别和传导几丁质信号，并最终诱发水稻基础免疫反应的机制尚不清楚。本项目拟首先通过生物化学和遗传学等手段，分析OsMBL1与已知几丁质受体CEBiP、LYP4、LYP6和OsTPR1，以及激酶OsCERK1的关系；利用酵母双杂交、免疫共沉淀联合质谱分析技术，筛选OsMBL1的互作蛋白，研究互作蛋白的生物学功能；通过蛋白翻译后修饰，研究OsMBL1调节和反馈的方式；最终阐明OsMBL1调控水稻免疫反应的机制。研究结果将进一步揭示水稻抗病反应的分子机理，为水稻抗病育种提供理论指导。

Chitin triggered immunity is an important rice innate immunity to fungal pathogens, lots of works try to reveal its signal pathway for defense response. Our previous research showed that Magnaporthe oryzae extracellular chitinase, MoChi1, is an effector required for full virulence by competing and degrading chitin oligomers to suppress chitin-induced reactive oxygen species in rice cells. And rice jacalin-related Man-Binding Lectin, OsMBL1, interacted and competed with MoChi1 for chitin binding to trigger rice innate immunity. However, it is unknown, as a new receptor, how the OsMBL1 recognizes and conducts the chitin signal to trigger innate immunity in rice cells. In this project, the techniques of biochemical and genetics will be used to analyze the relationships between the OsMBL1 and other chitin receptors, such as CEBiP, LYP4, LYP6 and OsTPR1, and also receptor kinase OsCERK1. The novel interaction proteins of OsMBL1 will be screened out and functional characterized, and the regulating and feedback control of OsMBL1 by protein modification will also be carried out. Our results will explain the signal pathway of OsMBL1 in control of rice immunity, which will help to better understand the molecular mechanism of rice disease resistance, and to service rice resistance breeding in the future.