9311与日本晴间一个杂种不育基因的鉴定与定位

以克服亚种间杂种不育来充分发掘亚种间杂种优势是提高水稻单产的一条有效途径。本研究从一套以日本晴为背景、9311为供体的染色体片段代换系中鉴定出一个系T9424,其与日本晴配置的F_1植株小穗与花粉育性较双亲显著降低,双亲间存在不亲和。重测序结果表明T9424在第1、第4和第5染色体上导入9311片段。日本晴/T9424F_2群体内单株基因型及育性鉴定结果表明,T9424与日本晴间杂种不育基因位于第5染色体上。利用F_2群体内790株单株将该杂种不育基因定位于第5染色体分子标记PSM8与A14之间110 kb的物理区段内。对日本晴/T9424 F_1植株花粉与胚囊育性鉴定结果表明该杂种不育基因同时控制雌、雄配子败育,将该基因暂命名为S39(t)。相关结果有助于加深对水稻亚种间杂种不育现象的认识,为该基因克隆及其育种利用奠定基础。

Identification and Mapping of a Hybrid Sterility Gene between 9311 and Nipponbare

Exploitation of subspecific heterosis is an effective method to improve rice yield by overcoming hybrid sterility between subspecies. In this study, F₁ plants of the cross between Nipponbare and T9424, a line from a set of chromosome segment substitution lines with Nipponbare background as recipient and 9311 as donor, showed the decreasing spikelet and pollen fertility compared with the two parents, indicating that there was the incompatibility between the parents. Three substituted chromosome segments on chromosome 1, 4, and 5, respectively, were identified by whole genome re-sequencing of T9424. Analysis of the genotypes and spikelet fertility of plants in Nipponbare/T9424 F₂ population indicated that hybrid sterility gene between T9424 and Nipponbare was located on chromosome 5. A total of 790 plants were then used for mapping the hybrid sterility gene, and the target gene was mapped to a candidate region with the physical distance of 110 kb between PSM8 and A14 on chromosome 5. The hybrid sterility gene, named S39(t) temporarily, controlled partial abortion of both pollen grains and embryo-sac of Nipponbare/T9424 F₁ plants. These results are useful for deepening understanding of the phenomenon of hybrid sterility, and lay the groundwork for the gene cloning and its use in breeding.