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杂种不育是水稻籼粳亚种间杂种优势利用的主要障碍.为了克隆1个籼粳杂种不育基因Sc,利用分子标记和近等基因系杂交产生的F2群体对Sc座位进行了精细定位.初步的连锁分析结果表明,Sc座位与第3染色体的4个分子标记以RM218-RG369-Sc-RG227-RG391的关系连锁,其中RG227与Sc座位之间的遗传距离为0.07cM.用RG227为起始探针筛选籼稻的TAC基因组文库,并通过染色体步移构建了一个覆盖Sc座位的跨度约320kb的克隆重叠群.对可能覆盖Sc的2个TAC克隆M45E14和M90J01进行了部分测序.用TAC克隆序列和RG227序列搜索水稻基因组序列数据库,锚定了粳稻BAC克隆OSJNBb0078P24(148kb)序列.通过比较TAC和BAC克隆的序列,在Sc座位区域发展了6个新的基于PCR的标记.用这些标记进一步把Sc座位定位在一个约46kb的区域内.从定位结果推测该BAC克隆和TAC克隆M45E14包含Sc基因.基因预测分析显示,在此46kb区域内有6个预测的ORF.
Hybrid sterility is a major obstacle to the heterosis utilization between rice indica and japonica subspecies.In order to clone an indica-japonica hybrid sterility gene Sc, the Sc locus was finely mapped using the F2 population generated by molecular marker and near-isogenic crosses. The preliminary linkage analysis showed that Sc locus was linked with RM218-RG369-Sc-RG227-RG391 by four markers on chromosome 3, and the genetic distance between RG227 and Sc was 0.07cM. The first probe screened the TAC genomic library of indica rice and constructed a clonal contig about 320kb spanning the Sc seat by chromosome walking.The two TAC clones M45E14 and M90J01 which may cover Sc were partially sequenced.The TAC clones Sequence and the RG227 sequence were searched for the rice genomic sequence database and the japonica BAC clone OSJNBb0078P24 (148kb) sequence was anchored. Six new PCR-based markers were developed in the Sc-seat region by comparing the sequences of the TAC and BAC clones. The Sc locus was located in a region of about 46 kb.From the localization results, it was inferred that the BAC clone and the TAC clone M45E14 contained the Sc gene.The gene prediction analysis showed that there are 6 The ORF.