异常线粒体基因ORF25可能导致烟草雄性不育

Aberrant Mitochondrial Gene ORF25 May Cause Tobacco Male Sterility

克隆和测定烟草胞质雄性不育系MS革新3号及其保持系革新3号线粒体基因ORF25的序列。结果表明:保持系的ORF25基因序列能推导出完整的氨基酸序列,应该具有正常的生物学功能;而雄性不育系的ORF25基因序列与保持系有较大差异,共有11个位点发生了变化,特别是在89位点发生的碱基C→A的变化及336位点发生的碱基T→A的变化,使得雄性雄性不育系在这2个位点出现终止密码子(TAA和TGA),导致不育系的ORF25基因不能推导出完整的氨基酸序列,使该基因不能产生完整的蛋白质多肽。因此,烟草雄性不育系的ORF25基因不能发挥其在保持系中所发挥的作用,这是否与烟草的雄性不育性有关还有待于进一步深入研究。

The ORF25 gene of tobacco cytoplasmic male sterile line （CMS） Gexin 3 and its maintainer line were cloned and sequenced. The result showed that the ORF25 gene of the maintainer line can be translated into integrated amino acid sequence and should have normal biological function. However, there are great differences of ORF25 gene sequence between the CMS line and its maintainer line and 11 base sites in ORF25 gene sequence of CMS were changed. In particular, the changes of base C→A at 89 site and T→A at 336 site produced two terminal codons （TAA and TGA） in CMS. So the ORF25 gene sequence of CMS line cannot be translated into integrated amino acid sequence. Thus, the ORF25 gene of CMS cannot possess the function as it did in the maintainer line. Whether or not these changes of ORF25 gene are related to tobacco male sterility needs further research.