Analysis and identification of anther-specific genes and male-sterility genes

利用水稻和拟南芥基因组序列的信息，以水稻和十字花科植物为材料，对花药中特异表达的基因和控制雄性不育和育性恢复的基因进行了分析，以开发目前最可靠的提高植物生产力的杂交F_1代育种方法。由于具有这些基因的非功能等位基因的突变体产生的花粉粒缺乏萌发能力，因此对这些基因的鉴定有助于在十字花科作物中产生具有高种子生产力的雄性不育系。利用本研究选育的甘蓝细胞质雄性不育恢复基因品系，我们发现orf72是线粒体基因的一个候选基因。我们还分离到了世界上第一个水稻Boro-CMS的育性恢复基因Rf1，发现Rf1蛋白被转移到线粒体并与线粒体mRNA相互作用。另外两种类型不育系的育性恢复基因被定位在水稻染色体上，并将含有这些基因的区域划分为染色体的短部分。这些基因的鉴定很快就会实现。在核基因雄性不育突变基因的研究中，我们开发了一种利用甘蓝型油菜叶柄提取液进行反向遗传突变选择的技术，以及一种新颖、简单、高效和经济的SNP分析技术。这些技术有望为培育一种新的F_1代杂交育种方法做出贡献。

Exploiting the information on the genome sequences of rice and Arabidopsis, genes specifically expressed in anthers and those responsible for male sterility and fertility-restoration were analyzed using rice and Brassicaceae plants to develop novel techniques for F_1 hybrid breeding, which is presently the most reliable breeding method for improving plant productivity.Three genes controlling exine production were newly identified, and isolated from Arabidopsis. Since mutants having nonfunctional alleles of these genes produce pollen grains lacking germination ability, identification of these genes enables the production of male-sterile lines having high seed productivity in Brassicaceae crops. Using a Brassica oleracea line having a fertility-restorer gene for mur-CMS (cytoplasmic male sterility), which was selected in the present study, we found orf72 to be a candidate of the mitochondrial gene responsible for mur-CMS. We also isolated the fertility-restorer gene for Boro-CMS in rice, Rf1, first in the world, and revealed that Rf1 protein is transferred to mitochondria and interacts with mitochondrial mRNA. Fertility-restorer genes for two other types of CMS in rice were mapped on rice chromosomes, and regions harboring these genes were delimited into short parts of chromosomes. Identification of these genes will be achieved soon. In the study of mutant genes responsible for nuclear-genic male sterility, we developed a reverse genetic mutant-selection technique using Brassica petiole extract and an original, simple, efficient, and cost-effective technique for SNP analysis. These techniques are expected to contribute to the development of a novel F_1 hybrid breeding method.