ABSTRACT

Seeds of F₁ hybrid cultivars of onions have been exclusively produced by utilising cytoplasmic male-sterility (CMS). A single locus, Ms, controls restoration of male-fertility of CMS onions. When a molecular marker tagging the AcPMS1 gene, a candidate gene for the Ms locus, was used to genotype diverse breeding lines, an unusual marker genotype showing an intermediate size of PCR product was identified in one breeding line (ORI854). The male-fertility phenotype of ORI854 was all male-sterile. Full-length genomic DNA sequence (16,464 bp) of this novel AcPMS1 allele from ORI854 was more closely related to a recessive AcPMS1 allele than to a dominant allele. However, there were more than 200 polymorphic sequences between this novel allele and the recessive allele, indicating that this novel AcPMS1 allele might not have recently diverged from the recessive allele. Phylogenetic analysis implied that onion male-sterility might have first appeared in a common ancestor before divergence of this novel allele and recessive allele of AcPMS1. Analysis of full-length cDNA sequences of additional 12 genes showing almost perfect linkage disequilibrium with the Ms locus indicated that no recombination might have happened among 13 genes including AcPMS1 in the novel Ms haplotype after divergence from the recessive Ms haplotype.

摘要

洋葱的 F ₁杂种栽培品种的种子专门通过利用细胞质雄性不育 (CMS) 产生。单个基因座Ms控制着 CMS 洋葱的雄性生育能力的恢复。当使用标记AcPMS1基因（Ms基因座的候选基因）的分子标记对不同育种品系进行基因分型时，在一个育种品系 (ORI854) 中鉴定出一种显示中等大小的 PCR 产物的不寻常标记基因型。ORI854的雄性生育表型均为雄性不育。来自 ORI854的这种新型AcPMS1等位基因的全长基因组 DNA 序列（16,464 bp）与隐性AcPMS1更密切相关等位基因而不是显性等位基因。然而，在这个新的等位基因和隐性等位基因之间有 200 多个多态性序列，表明这个新的AcPMS1等位基因最近可能没有与隐性等位基因发生分歧。系统发育分析表明，洋葱雄性不育可能首先出现在一个共同祖先中，然后再出现这种新的AcPMS1等位基因和隐性等位基因的分歧。的附加的12个基因的全长cDNA序列示出了与几乎完美的连锁不平衡的分析女士轨迹表明没有重组可能13个基因中，包括发生AcPMS1在小说女士从隐性发散后单体型女士 单倍型。