增加穗粒数是实现水稻高产遗传改良的有效途径之一。DEP1是调控水稻穗粒数的关键基因，正在我国水稻高产育种中发挥着重要作用。目前在生产上大面积种植的带有dep1-1基因的高产品种表现出直立或半直立穗型，每穗粒数差异较大，暗示dep1-1的功能可能受其他基因的调控。前期利用半直立穗型水稻材料克隆了一个控制水稻穗粒数的基因DEP5，进一步证明DEP1和DEP5之间存在直接的蛋白互作，二者共同参与细胞分裂素途径相关基因的表达调控。在此基础上，本项目将进一步研究DEP5基因的功能；重点解析DEP1-DEP5互作调控细胞分裂素进而影响水稻穗粒数的分子机制和遗传网络；挖掘和利用优异等位变异进行聚合育种，最终为进一步提高dep1-1的产量提供理论依据和基因资源。

Increasing the grain number per panicle is one of the effective ways to improve rice yield. As a key gene in regulating grain number and yield, DEP1 has played important roles on rice breeding in China. The mutant dep1-1 allele has been found in most of high-yielding rice varieties with erect and semi-erect panicles, which indicates that the function of dep1-1 on erect panicle formation should be affected by some other genes. In our previous research, a major QTL qDEP5 responsible for regulating the grain numbers was isolated, and the candidate gene was cloned by map-based cloning. The SFLC and Co-IP assays have confirmed that DEP5 could interact with dep1-1. RNA-seq analyses showed that some cytokinin synthesis and signaling related genes were commonly regulated by both DEP1 and DEP5. In this proposal, the molecular characterization of DEP5 gene will be analyzed. More importantly, we will study on the molecular mechanism of DEP1-DEP5 controlling cytokinin and grain number in rice and seek some new elite alleles, in order to provide theoretical basis and important gene resources for molecular polymerization breeding of high-yielding rice.