水稻籼粳亚种间具有强大的杂种优势，但是杂种不育限制了亚种间杂种优势的有效利用。我们前期对水稻杂种花粉不育基因Se进行了精细定位，将其限定在水稻第12染色体13.1 kb的物理距离内，通过序列测定发现定位亲本T65在此区域内注释包含2个候选基因，而定位亲本E9在该区域内注释包含4个候选基因。在此基础上，本项目拟通过定量检测、互补转化和蛋白互作研究验证候选基因，明确水稻杂种花粉不育基因Se，通过亚细胞定位、细胞学观察、表达谱研究、互作关系验证和等位基因分析等手段阐明杂种花粉不育基因Se的分子作用机理和进化机制，为其它水稻杂种不育基因的克隆、栽培稻籼粳亚种的分化研究、克服亚种间的生殖隔离和杂种优势的有效利用提供理论指导。

F1 hybrid sterility including embryo-sac abortion and pollen sterility frequently occurs in the crosses between subspecies of indica and japonica varieties of rice (Oryza sativa L.), which hinders the transferring of useful genes between the two subspecies, and is a major obstacle for the utilization of the strong heteosis exhibited in the hybrids. Using a japonica variety Taichung 65 (T65) and its near-isogenic line E9, a major locus conferring hybrid male sterility, Se, was identified on chromosome 12 between molecular marker IND9 and LM48 with 0.3 cM and 0.2 cM genetic distance, respectively. High-resolution mapping of 7,274 F3 plants of the T65×E9 cross delimited the Se locus to a 13.1 kb region containing two predicted genes in T65 genome, while the target region in E9 genome contains four predicted gene inside. In this proposed project, we proposed to clone Se by quantitative expression analysis, complementation transformation analysis and protein interaction analysis of the six candidate genes. Furthermore, we proposed to molecularly characterize the function and evolution of Se through a combination of different ways, including subcellular locatization analysis, cytological investigation, RNA-Seq analysis, interaction analysis between Se and other F1 hybrid male sterility genes, allelic variation and molecular evolution analysis. Information and knowledge generated from the proposed project will assist the clarification of the mechanism controling hybrid male sterility and indica-japonica differentiation in rice, and facilitate overcoming reproductive isolation and utilizating strong inter-subspecific heterosis in hybrid rice breeding.