落粒分子机制研究对指导适合机械化生产的水稻现代化育种有重大意义。目前仅克隆了5个水稻落粒基因qSH1、SH4/SHA1、SHAT1、OsCPL1和SH5，其中qSH1和SH4在水稻驯化中最为关键。我们图位克隆了一个新的显性控制水稻难落粒的AP2家族转录因子SH6，并得到功能互补。qRT-PCR表明，SH6和SH4可能是同一通路的基因，且SH6可能抑制SH4的表达。本项目拟在此良好的研究基础上，重点解决三个问题，（1）以RNAi、原位杂交、qRT-PCR等方法明确SH6的基本功能；（2）以双突变体遗传验证、ChIP、EMSA、酵母双杂交、BiFC等实验手段明确SH6与SH4调控关系及SH6的互作蛋白，从而解析水稻离层分化而导致落粒的分子机制。（3）分析SH6是否在籼、粳亚种间存在共同位点的进化差异。因而本研究对明晰水稻落粒性分子机理及适合机械化收获的新品种培育具有十分重要的意义。

Research on molecular mechanisms of shattering is a great subject to direct modern breeding of rice adapting to the mechanized harvesting.To date,only 5 genes（qSH1,SH4/SHA1,SHAT1,OsCPL1 and SH5) for rice seed shattering were cloned, of which SH4 and qSH1 were key for regulating shattering in rice domestication. We cloned a SH6 for difficult seed shattering encoding a AP2 family transcription factor with dominant inheritance, and was testified by complementary functions. qRT-PCR results showed that SH6 and SH4 may be in the same regulatory route, and SH6 maybe suppress the expression of SH4. Based on the good research bases, three important problems will be resolved in the project. (1) Clear the basic function of SH6 by methods such as RNAi, In situ hybridization, and qRT-PCR et al. (2) Clarify the regulating relationship of SH6 and SH4 and interaction protein of SH6, and therefore how to regulate the formation of abscission layer leading to seed shattering by inheritance analysis of double mutant, ChIP, EMSA Yeast two-hybrid, BiFC et al. (3) Analyze whether existing a common site in SH6 between indica and japonica rice for controlling seed shattering. Consequently, the project will be of great value for explicating the molecular mechanisms of regulating shattering by SH6 and for breeding novel rice varieties to adapt to rice mechanized harvesting.