水稻穗发芽突变体的筛选及候选基因鉴定

Screening and Gene Mapping of Pre-harvest Sprouting Mutants in Rice

水稻穗发芽是一种多发性的自然灾害,给水稻生产造成了严重的经济损失。由于穗发芽机制还不完全清楚,如何培育抗穗发芽的水稻品种,已成为世界性的难题。本研究利用水稻甲基磺酸乙酯诱变突变体库,通过田间筛选,获得9个水稻穗发芽突变体。并对其中2个突变体进行研究,利用基于基因组重测序的SIMM方法和高分辨率溶解曲线分析技术,分别获得其穗发芽候选基因LOC_Os03g08570和LOC_Os07g10490。LOC_Os03g08570编码一个八氢番茄红素脱氢酶,LOC_Os07g10490编码一个ζ-胡萝卜素脱氢酶,它们都参与脱落酸前体类胡萝卜素的合成。本研究的结果进一步证明类胡萝卜素的合成在水稻休眠中的关键作用。同时,本研究获得的这些穗发芽突变体为后续深入研究水稻穗发芽的分子机制及开展分子设计育种提供了宝贵材料。

Pre-harvest sprouting(PHS) is a frequently-occurring disaster that results in a serious economic loss in rice production. Breeding for PHS-resistant rice varieties has limited worldwide due to the mechanism of PHS that remains unclear. Here,nine independent mutants conferring PHS were identified by screening of an Ethyl methylsulfone mutant library,and two of them were subjected for further study. By taking use of whole genome resequencing,SIMM method and HRM technology,two PHS mutant genes(LOC_Os03 g08570 and LOC_Os07 g10490) were molecularly cloned. LOC_Os03 g08570 codes a phytoene desaturase,and LOC_Os07 g10490 codes a ζ-carotene desaturase. Both were reported to be involved in the biosynthesis of carotenoid as the precursor of ABA. In summary,our data highlights the critical role of carotenoid that participates in rice dormancy. Further studies of these PHS mutants would allow revealing the mechanism of PHS and breeding for PHS-resistant rice varieties.