玉米S型细胞质雄性不育恢复基因Rf3的精细定位及其候选基因预测

Fine Mapping of Fertility Restorer Gene Rf3 of S- Type Cytoplasmic Male Sterility and Candidate Gene Prediction in Maize

细胞质雄性不育(Cytoplasmic male sterility,CMS)广泛存在于高等植物,CMS-S是玉米CMS的一种,其育性可以被恢复基因Rf3完全恢复。目前Rf3基因尚未成功克隆。本试验根据玉米CMS-S配子体不育特点,提出一种全新的同质群体构建方法,通过该方法获得群体的所有个体均携带Rf3恢复基因,省去田间表型鉴定工作,并可在同一世代获得足够的重组个体。该方法可直接用种子提取基因组DNA,大大提高Rf3定位的效率。利用该同质定位群体,将恢复基因Rf3精细定位到分子标记A165与CG2之间,参照玉米自交系B73的基因组序列,两个标记之间的物理距离约为1.4 Mb。

Cytoplasmic male sterility （ CMS） is widespread in higher plants .CMS-S, one of the major CMS in maize , can be restored by Rf3 gene which has not been cloned yet .Based on the gametophytic nature of maize CMS-S, a novel homogeneous population constructing method was put forward for mapping .All the individuals obtained through this method carried the Rf3 gene making the phenotype identification unnecessa-ry , and enough recombinants could be obtained in the same generation .Using this method , the DNA extracted from seeds could be used directly , so the efficiency of Rf3 mapping could be improved greatly .With this hom-ogeneous population , Rf3 gene could be fine mapped in the locus between molecular marker A 165 and CG2 . The physical distance between the two SSR markers was about 1.4 Mb according to the genome sequence of maize inbred line B73.