油菜素内酯受体BAK1的S-亚硝基化修饰在番茄抗盐中的作用及机制

前期研究表明油菜素内酯（BR）和一氧化氮（NO）均调控植物逆境响应，且存在互作，但未见蛋白质S-亚硝基化修饰调控BR信号通路的报道。本研究拟通过生物素转化法结合质谱分析探讨盐胁迫下番茄幼苗BR共受体蛋白BRI1-associated receptor kinase 1（BAK1）的S-亚硝基化及其位点，并通过定点突变（去亚硝基化）验证S-亚硝基化发生的位点，进而分析S-亚硝基化对BAK1表达水平的影响。采用免疫共沉淀和pull-down等技术手段分析该S-亚硝基化修饰对Brassinosteroid-insensitive 1（BRI1）-BAK1蛋白互作及BR信号转导的影响，进而探索番茄幼苗蛋白质S-亚硝基化参与BR对盐胁迫的响应。本研究拟探讨蛋白质S-亚硝基化修饰在逆境条件下园艺作物蛋白互作和生长发育中的功能，揭示BR信号通路中关键蛋白S-亚硝基化对园艺作物响应非生物胁迫的分子机制。

Previous studies have shown that brassinosteroid (BR) and nitric oxide (NO) could regulate plant to response stresses. There exists interaction between BR and NO during that process. However, the protein S-nitrosylation modification of BR signaling pathways has not been reported until now. This study will investigate the S-nitrosylation of BRI1- associated receptor kinase 1 (BAK1, the BR co-receptor protein) in tomato seedlings under salt stress by biotin switch method. The S-nitrosylated sites of BAK1 will be explore by mass spectrometry. Then, the S-nitrosylated site of BAK1 will be verified by site-directed mutagenesis (de-nitrosylation). The effects of the S-nitrosylation of BAK1 on its expression levels also will be analyzed further. In addition, the roles of the S-nitrosylation modification of BAK1 in brassinosteroid-insensitive 1 (BRI1)-BAK1 interaction and BR signal transduction will be investigated by Co-immunoprecipitation and pull-down, thereby further exploring the involvement of S-nitrosylation of BAK1 in the response to salt stress in tomato seedling. These results may reveal the roles of protein S-nitrosylation modification in horticultural crop growth and development and protein interactions under stress conditions. Therefore, the aim of this study is to reveal the molecular mechanism of the protein S-nitrosylation modification of key proteins in the BR signaling pathway in respond to abiotic stresses in horticultural crops.