DSHT1调控高温影响水稻结实的分子机制和应用研究

随着全球气候变暖，极端天气愈见频繁。水稻花期极易遭遇夏季高温危害，导致减产甚至绝收。但目前高温影响水稻结实的分子机理和用于培育耐高温品种的自然优异等位基因鲜有报道。我们前期鉴定了一份结实率在正常温度下无差异，高温下大幅下降的突变体dsht1，其表型由一个磷脂翻转酶突变所致。功能分析表明：DSHT1与ALIS4互作，ALIS4敲出株系结实率降低；DSHT1-ALIS4复合体翻转磷脂酰丝氨酸等底物。DSHT1过表达株系抽穗期更耐高温，序列和表达量分析表明Kasalath的DSHT1启动子序列特异且表达量高，可能为耐高温优异等位基因。本项目拟在前期研究基础上，从遗传、组织细胞学和分子生物学等角度解析DSHT1-ALIS4复合物参与调控高温影响水稻结实的分子生物学机制,分析DSHT1自然优异等位基因耐高温能力及实际应用潜力，为培育花期耐高温品种提供理论基础和优异等位基因资源。

The extreme weather becomes more and more frequent along with the globe warming. Rice is vulnerable to high temperature at the flowering stage in summer, that could cause loss of yield, or even absence of yield. However, few molecular mechanism about seed setting under high temperature, and few natural elite allele which is helpful for breeding heat tolerance rice variety have been reported so far. We previously identified a mutant, dsht1, which exhibited significantly decreased seed setting under high temperature, but no difference between WT and dsth1 under normal temperature. The dsht1 phenotype was caused by a mutation in a phospholipid flippase. The function analysis showed that DSHT1 interacted with ALIS4 which knockout lines showed reduced seed setting; the DSHT1-ALIS4 complex very possibly flipped phosphatidylserine etc. The DSHT1 overexpression lines was more resistant to high temperature. Sequence and expression analysis showed that the DSHT1 promoter sequence of Kasalath is different with that of other varieties, and the DSHT1 expression in Kasalath are significantly higher than that of other varieties. Based on these results, we plan to study the molecular mechanism of DSHT1-ALIS4 complex on rice seed setting under heat temperature from genetics, histocytology and molecular biology angles; and analyze the ability and application potential of natural alleles of DSHT1 on heat tolerance. These results will provide theoretical basis and natural allelic variation for breeding heat tolerance varieties at the flowering stage.