氮和磷是植物生长发育的重要限制因子。近年来对植物氮磷信号转导途径的研究表明，众多基因参与植物对缺氮和缺磷环境的适应性机制，并且氮磷信号转导途径与包括碳代谢途径在内的其他途径存在交互作用。申请人前期工作从水稻中筛选到了一个参与氮磷缺乏胁迫下淀粉合成相关基因，其编码二磷酸腺苷葡萄糖焦磷酸酶，并暂将其命名为OsAGPase3。初步结果显示，该基因突变影响水稻对缺氮胁迫的响应和磷素积累。本项目拟利用OsAGPase3过量表达和突变体植株，同时采用BiFC、蛋白体内和体外活性检测、基因芯片等手段，挖掘OsAGPase3在水稻缺氮和缺磷胁迫响应中的功能。本研究有望阐明水稻中首个参与维持氮磷动态平衡的二磷酸腺苷葡萄糖焦磷酸酶的生理功能及其分子机制，为水稻养分缺乏信号转导途径和碳代谢途径的交互作用的研究提供理论依据，同时为培育氮磷高效作物提供候选基因。

Nitrogen (N) and phosphorus (P) are often limiting factors in soil for plant growth and development. It has been reported that a large number of genes are involved in plant responses to N and phosphate (Pi) starvation stresses. Besides, increasing lines of evidences suggest the crosstalk between nutrient starvation signaling (i.e. N and Pi starvation signaling) and carbon (C) signaling. In our previous work, a N and Pi starvation-responsive gene encoding adenosine diphosphate-glucose pyrophosphorylase (AGPase), which is responsible for the biosynthesis of starch in rice (Oryza sativa), was isolated, and designated as OsAGPase3. A mutant line of OsAGPase3 showed disrupted responses to N starvation and accumulation of P. In the present work, both OsAGPase3 mutants and overexpression lines will be used for functional characterization of this gene in response to N and Pi starvation stresses. In addition, bimolecular fluorescent complementation, measurement of in vitro and in vivo protein activity, as well as microarray analysis will also be utilized. We believe that we stand a good chance to elucidate the pivotal role and underlying molecular mechanism of OsAGPase3 in N and Pi starvation signalings and their crosstalk with C signaling, providing candidate genes for molecular breeding of crops with high N- and P-use-efficiency.