栽培稻种间杂种不育基因S1的图位克隆

水稻种间杂种不育限制了其杂种优势的有效利用,S1是其中一个最重要的杂种不育基因座。为探讨S1对杂种的雌雄配子选择性杀灭作用,本研究首先采用图位克隆法,对粳稻IRAT216及其包含非洲栽培稻S1座位的近等基因系IRAT216S1构建的BC9F2分离群体,进行了S1精细定位与克隆。首先在定位区间内筛选了所有网上公开的SSR标记,并结合自行测序比较,开发出了31对有多态性的分子标记,把S1锁定在P0535G04克隆上标记2180与2198之间18 kb的精细定位区段,内有ORF11、ORF12两个候选基因。对两基因基因组测序、RT-PCR、基因芯片分析,排除了ORF11,确定了ORF12是唯一候选基因,同时也排除了此座外存在辅助因子的可能性。本研究分子标记的开发将为水稻的分子标记辅助育种提供帮助,而S1基因的克隆将为杂交育种中克服杂种不育提供了可能,也为进一步杂种优势的利用打下基础。

Map-Based Cloning of S1 for Hybrid Sterility between Cultivated Rice Species

Hybrid sterility restricts the utilization of interspecific strong heterosis in rice.S1 is a key locus with the largest effect on sativa-glaberrima hybrid sterility,which selectly kills both female and male gametophytes of the hybrids.In this study,a japonica line IRAT216 and its isogenic line IRAT216S1 harboring the S1 locus derived from African cultivated rice were used to produce a BC9F2 mapping population as material of map cloning of S1.31 molecular markers were developed to finally delimit S1 to a 18 kb region between markers 2180 and 2198.Two candidate genes ORF11 and ORF12 were found in the region.By genome sequencing and RT-PCR and gene chip analysis,ORF11 was excluded and only ORF12 was assured to be the candidate gene.The development of molecular markers in this study will help molecular marker-assisted breeding of rice,and the cloning of S1 gene will provide a possibility to overcome hybrid infertility in cross-breeding,and lay a foundation for further utilization of heterosis.