小麦K、V型细胞质雄性不育系线粒体基因的比较分析

Comparative Analysis of Mitochondrial Genes from Wheat K-and V-Type Cytoplasmic Male Sterility Lines

细胞质雄性不育(cytoplasmic male sterility,MS)是高等植物中普遍存在的一种母性遗传现象,跟线粒体基因密切相关。小麦K型和V型细胞质雄性不育性是由于粘果山羊草和偏凸山羊草或易变山羊草的细胞质导入普通小麦中产生的,被认为是最有利用潜力的小麦不育种质,但是其不育性产生的机理还不清楚。本研究在已知小麦K型细胞质雄性不育系和保持系线粒体基因组序列的基础上,比较分析了K型,V型不育系和保持系中33个线粒体基因和22个开放阅读框(open reading frame,orf;K型不育系特有的,被认为是K型不育系的不育候选基因)。结果表明,线粒体基因中除atp6、nad6和rps3在保持系和不育系之间有较大差异外,其它基因在保持系和不育系中都是高度保守的,其一致性达98%以上,atp6和nad6在两个不育系中也是高度一致的;22个orf中只有orf249在K型和V型不育系之间具有一定差异,其余的orf高度一致,说明小麦K型和V型不育系的线粒体基因是高度保守的,推测二者可能具有相似的不育基因或不育机理。研究结果为小麦K型和V型不育系在杂交育种中的利用奠定了一定的理论基础。

Cytoplasmic male sterility(CMS),a maternally inherited phenotype of pollen sterility in higher plants,is associated with special mitochondrial genes. Wheat K- and V- type CMS,respectively produced by the introduction of Aegilops kotschyi and Ae. ventricosa or Ae. variabilis cytoplasts into common wheat,are believed to be the most useful CMS resources of wheat,but their mechanism of male sterility is still unknown. Based on the mitochondrial genome sequences of a wheat K-type CMS line and its maintainer line,33 mitochondrial genes and22 open reading frames(orfs,unique genes in wheat K-type CMS line and believed to be candidate CMS genes)between wheat K-,V- type CMS lines and their maintainer line were compared. The results showed that except for atp6,nad6 and rps3 which had obvious differences between the CMS lines and their maintainer line,the rest 30 mitochondrial genes had over 98% identity between K-,V- type CMS lines and their maintainer line,atp6 and nad6 were also highly conserved between K- and V- type CMS lines. While among the 22 orfs,only orf249 showed91% identity between K- and V- type CMS lines,other orfs had over 98% identity. These results suggest that mitochondrial genes are highly conserved in wheat K- and V-type CMS lines,and they may have similar CMS gene or mechanism of male sterility. These results lay a foundation for the utility of wheat K- and V-type CMS lines in wheat hybrid production.