S-亚硝基化是蛋白质中半胱氨酸残基的巯基与一氧化氮(nitric oxide, NO)基团共价连接的一种翻译后修饰。S-亚硝基化曾被认为是一个非酶促反应。近年来发现NO基团从特异转亚硝基化酶转移至靶蛋白是决定亚硝基化特异性的一种重要机制。目前对转亚硝基化的生化机制了解甚少，而植物中尚未发现转亚硝基化酶。我们前期研究发现拟南芥gsnor1突变导致NO含量升高、全蛋白组过度修饰、生长发育缺陷等表型，而上述表型可被repressor of gsnor1 (rog1)突变部分恢复。在本研究中，我们将：1）解析ROG1作为候选转亚硝基化酶的功能，分离鉴定其底物RIPs；2）解析转亚硝基化调控GSNOR1/RIP3通过自噬途径降解的分子机理；3）探索转亚硝基化修饰RIP2调控陆生植物环境适应性的重要作用。通过上述研究，揭示依赖于NO的转亚硝基化调控植物胁迫反应与陆生植物环境适应性的分子机理。

S-nitrosylation is a redox-based protein posttranslational modification that covalently links a nitric oxide (NO) group to a Cys thiol of a protein. S-nitrosylation has been thought as a non-enzymatic reaction. Recent studies reveal that an NO group is capable of transferring from a transnitrosylase to a target protein, which acts as an important mechanism to determine the specificity of nitrosylation. However, little is known about the biochemical basis of transnitrosylation, yet no transnitrosylase has been identified in plants. We previously found that the Arabidopsis gsnor1 mutation causes an increased NO level, proteasome-wide over-modification and defective development, which are partially rescued by the repressor of gsnor1 (rog1) mutation. In this application, we propose: 1) Functional analysis of the putative transnitrosylase ROG1 and the identification of its putative substrates (RIPs); 2) Reveal the molecular mechanism of transnitrosylation-mediated autophagic degradation of GSNOR1/RIP3; 3) Investigate the potential roles of transnitrosylation of RIP2 during land plant evolution. Collectively, the proposed studies aim at comprehensive understanding the molecular mechanisms of the NO-based transnitrosylation in regulating stress responses and its potential role in physiological adaptations of plants to land.