氮素调控基因对植物的氮素吸收、转运和同化有非常重要的调控作用，加强对植物氮素调控基因的研究对于提高作物的氮素利用率和农业的可持续发展意义重大。本项目利用正向遗传学方法克隆出了新的硝态氮负调控基因NSIG，拟从形态、生理生化及分子水平上系统研究NSIG的功能，阐明其调控硝态氮信号和代谢的机制；利用生物化学和遗传学的方法研究NSIG与IWS1（转录延伸因子）蛋白的互作及互作的关键区域，明确NSIG与IWS1在硝态氮调控方面的关系；通过RNA-seq和ChIP-seq分析，揭示NSIG和IWS1通过介导组蛋白甲基化调控硝态氮信号的分子机制。预期结果将为阐明植物硝态氮调控的机制及解析硝态氮调控的分子网络奠定基础，为培育高氮效的作物新品种和提高作物的氮素利用率提供理论依据和支撑。

Nitrogen regulatory genes play essential roles in nitrogen uptake, transport, and assimilation of plants. Identification and characterization of nitrate regulatory genes and underlining mechanisms are of great importance for improving the nitrogen use efficiency of crops and developing sustainable agriculture. In this research, we cloned a novel negative nitrate regulatory gene named NSIG by a forward genetics screen. We will investigate the function of NSIG gene in the morphological, physiological, biochemical and molecular levels to clarify its mechanisms in nitrate signaling and metabolism. We will further test the interaction of NSIG and IWS1 proteins and find the key domain responsible for their interaction. The relationship of NSIG and IWS1 genes in the nitrate regulatory pathway will be studied by using the genetic methods. Furthermore, we will perform the RNA-seq and ChIP-seq to explore the underlying molecular mechanisms that NSIG and IWS1 regulate the nitrate signaling mediated by the histone methylation. These expected results will lay the foundation for deciphering the mechanisms of nitrate regulation and improving the nitrate regulatory network. This research will provide theoretical basis and support for breeding new crop varieties with high nitrogen use efficiency and improving crop nitrogen utilization.