水稻籼粳亚种间杂种具有强大的杂种优势，但是杂种不育限制了亚种间杂种优势的有效利用。我们的前期研究对水稻杂种花粉不育基因Sc进行了精细定位，确定粳稻唯一候选基因ORF27，但籼稻该处存在一个较大的插入片段，可能含有ORF27的两个同源拷贝。在此基础上，本项目利用华中农大提供的含有该基因的BAC克隆，对插入片段进行基因组测序，基因预测，遴选候选基因，证实籼稻确实存在ORF27的两个拷贝（ORF27-1，ORF27-2）；分别对籼稻两个拷贝与粳稻该基因进行等位基因的功能互补实验，同时构建ORF27的RNAi载体与超表达载体验证候选基因的功能，结果表明ORF27与花粉的发育有关，ORF27-1可能是杂种不育基因Sc； RNA表达分析表明籼粳亚种该基因RNA水平差异明显，Sc的杂种不育可能与RNA的表达水平有关，表达量过高或过低都会导致花粉败育；花药细胞结构研究表明花粉败育是由于中期花药绒毡层细胞膨胀，影响养分与水分的输入与输出所致。本研究为其他杂种不育基因的克隆提供借鉴，为水稻亚种间杂种优势利用提供理论指导。

Hybrid sterility is the biggest barrier for using hybrid vigor between japonica-indica crosses of rice. It is very important to clone the genes for the sterility and study of the molecular mechanism. Gene Sc for pollen sterility had been fine-mapped and ORF27 was selected as the only candidate gene for japonica according to the sequencing analysis. But in the location region of indica, a large insertion fragment was found, and perhaps including two bomogenous copies of ORF27. Based on the former experiments, a BAC clone carried ORF27 was sequenced and the insertion fragment was analyzed, two bomogenous copies of ORF27 (namely ORF27-1 and ORF27-2) were verified to lie in indica. Then a series of experiments were designed to test the function of ORF27 and the mechanism of pollen sterility including the interallelic complementation experiment, and RNA inference and over-expression experiment by Agrobacterium-mediated transformation, and the expression model of ORF27, and cell lays structure of the anther wall observation, and so on. Our results showed ORF27 was very critical for pollen development, and ORF27-1 was the hybrid sterility gene Sc; pollen sterility was contact with RNA expression, and the lower and over-expression would all result in pollen grains sterility; the tapetum of anther wall became large expanding in the mature pollen stage, which might result in the microspore mother cell and tetrads microspore did not obtain enough nutrient. Our researchs were to offer the theoretical direction for the action mechanism of the other hybrid sterility gene and using the hybrid vigor in rice.

水稻籼粳亚种间杂种具有强大的杂种优势，但是杂种不育限制了亚种间杂种优势的有效利用。我们的前期研究对水稻杂种花粉不育基因Sc进行了精细定位，确定粳稻唯一候选基因ORF27，但籼稻该处存在一个较大的插入片段，可能含有ORF27的两个同源拷贝。在此基础上，本项目利用华中农大提供的含有该基因的BAC克隆，对插入片段进行基因组测序，基因预测，遴选候选基因，证实籼稻确实存在ORF27的两个拷贝（ORF27-1，ORF27-2）；分别对籼稻两个拷贝与粳稻该基因进行等位基因的功能互补实验，同时构建ORF27的RNAi载体与超表达载体验证候选基因的功能，结果表明ORF27与花粉的发育有关，ORF27-1可能是杂种不育基因Sc； RNA表达分析表明籼粳亚种该基因RNA水平差异明显，Sc的杂种不育可能与RNA的表达水平有关，表达量过高或过低都会导致花粉败育；花药细胞结构研究表明花粉败育是由于中期花药绒毡层细胞膨胀，影响养分与水分的输入与输出所致。本研究为其他杂种不育基因的克隆提供借鉴，为水稻亚种间杂种优势利用提供理论指导。