在农业生产中，大量施用氮肥一直是农作物高产的重要措施之一。然而，氮肥使用量的逐年增加并未带来产量的大幅提高，经济效益和生态效益反而呈下降趋势。因此，亟需从育种源头上来提高农作物本身的氮肥利用效率。前期研究表明dep1能显著提高水稻氮肥利用效率和产量，但对dep1如何促进氮肥吸收与同化的分子机制仍不了解。本项目利用野生稻、农家种、主栽品种以及突变体库等水稻材料，综合运用遗传学、分子生物学、生物化学、电生理学、基因组学、转录组学和生物信息学等手段，鉴定水稻G蛋白信号转导途径的新成员，深入研究这些基因的功能及其调控水稻氮肥吸收与同化效率的分子机制，解析dep1调控的上、下游靶基因及其互作网络，揭示dep1-DAK33-DIP73分子调控模块提高水稻产量和氮肥利用效率的新机制，挖掘和利用水稻氮肥高效吸收利用的优异等位基因，为“资源节约型”水稻高产分子设计育种奠定理论基础和提供新基因资源。

The ‘Green Revolution’ boosted rice yields, and fed an expanding world population, which was driven by rapid adoption of semi-dwarf green revolution varieties (GRVs) in the past 50 years. However, GRV soil nitrogen use is inefficient, and high yields are heavily dependent upon nitrogen fertilizer inputs that unsustainably damage the environment. There therefore is an urgent need to develop the new rice varieties that retain the beneficial semi-dwarfism of GRVs, but which can achieve increased yield with reduced nitrogen fertilizer inputs. However, nitrogen use efficiency (NUE) and related traits were controlled by quantitative trait loci (QTL) derived from natural variations in rice. Recently, the elite dep1 allele has been shown to improve grain yield and NUE in rice, but its molecular mechanism for enhancing NUE still remains unclear. In this proposal, we will focus on identification of the key components of G-protein signaling and its natural variants using the various genetic and biochemical approaches, and investigate the function of DEP1-interacting proteins and their roles in G-protein signal transduction pathway, and reveal the molecular mechanisms and integrative network of these genes responsible for nitrogen uptake and assimilation in rice.