增加每穗穗粒数是水稻高产育种的有效途径之一。由于穗粒数是受多个基因和环境共同控制的复杂数量性状，目前已克隆的调控水稻穗粒数的基因还很少，而能够在生产中应用的关键基因则少之又少，DEP1基因是其中之一，其显性突变的dep1能够显著增加穗粒数和产量。迄今，关于DEP1调控水稻穗粒数的分子机制和遗传网络还不清晰。本项目通过遗传筛选获得了一个能够使dep1的穗粒数减少的突变体sod (suppressor of dep1)，利用图位克隆方法克隆了SOD候选基因并进行了遗传互补验证。酵母双杂交筛库获知，SOD能够与DEP1和LAX1发生蛋白互作。在此基础上，本项目将进一步研究SOD基因的功能，解析SOD、DEP1和LAX1基因之间的互作关系及其调控穗粒数的遗传网络。这些研究结果将为揭示水稻穗粒数的调控机制提供新的生长点，并为水稻高产分子设计育种提供理论基础和基因资源。

Increasing the grain number per panicle is one of the effective ways to improve rice yield. Grain number is a complex quantitative trait controlled by multiple genes and collaborative environment and in recent years a small number of QTLs for grain number per panicle have been identified, however, ony a few genes can be used in rice production, and DEP1 (Dense and Erect Panicle 1) is one of them. The dominant allele dep1 enhances grain yield by increasing grain number and has been widely used in rice production. Recently, a sod (suppressor of dep1) mutant which shows reduced panicle branching and grain number is identified by genetic screenings, furthermore, the SOD gene is isolated by map-based cloning. In addition, DEP1 and LAX1 are identified as SOD interacting proteins by yeast two-hybrid screening and BiFC showes that SOD protein can directly interact with LAX1 protein in protoplast. In this proposal, the molecular characterization of SOD gene will be analyzed, and more importantly, the molecular mechanism of action of DEP1-SOD regulatory module will be the focus of analysis through analyzing the relationship among DEP1, SOD and LAX1, and identifing the target genes of DEP1-SOD-LAX1 regulatory module by RNA-seq transcriptome analysis. The purpose of this research is to help us further understand the molecular mechanism of rice panicle development and to provide important gene resources for molecular design breeding of rice.