水稻作为我国主要粮食作物之一，其产量极易受到全球逐渐频繁的夏季高温影响，严重影响着我国水稻粮食生产安全。但用于培育耐高温品种的优异基因资源和相关分子调控网络极少报道。我们前期鉴定了一份结实率在高温下大幅下降，正常温度无变化的突变体dsht2，其表型由一个编码微管蛋白基因中点突变所致。功能分析表明：dsht2中微管排列出现异常；TF1直接绑定DSHT2启动子，并调控其表达，且tf1突变体也表现出高温结实差表型；DSHT2启动子在9311和NIP间存在29bp插入和SNP，9311中DSHT2启动子表达量显著高NIP型。含有DSHT2位点的9311-NIP代换系在高温处理下较9311结实率显著下降。本项目拟在此研究基础上，从表型、分子生物学方面解析TF1-DSHT2途径在水稻抽穗期耐高温中的分子机制；明确DSHT2自然优异等位基因,为培育抽穗期耐高温水稻品种提供分子理论和优异等位基因资源。

Rice is one of main crop in our country, its yield is easy to affect by more and more frequently high temperature in summer, that directly threates rice food security in our country. However, the elite natural allele resistant to high temperature, and the related molecular network is few reported, both of these are helpful for breeding variety with high temperature resistance. We previously identified a mutant, dsth2, which showed significantly decreased seed setting rate under high temperature, but no difference under normal temperature. The phenotype of dsht2 was caused by single SNP substitution in a gene encoding tubulin protein. The function analysis showed that the microtubule array was defective，TF1 directly binded the DSHT2 promoter sequence, and regulated its expression. The mutant of TF1 also showed reduced seed setting under high temperature. There are 29bp Indel and SNP between 9311 and NIP promoter sequence of DSHT2, the expression of DSHT2 in NIP was significantly lower than that of 9311, and the 9311 single segment substitution lines harboring DSHT2-Nip locus showed lower seed setting rate than that of 9311 under high temperature. In this proposed project, we plan to unveil the molecular mechanism of TF1-DSHT2 pathway at the aspect of seed setting under high temperature, and clear the utilization potentiality of elite natural allele of DSHT2. This proposed project will provide molecular theory and elite natural allele for breeding rice variety with high temperature resistance.