中文摘要：

【目的】探讨线粒体CoxⅡ和atpA基因与苎麻CMS的关系。【方法】根据GenBank报道的双子叶植物线粒体CoxⅡ和atpA基因编码区高度保守序列设计简并引物,通过PCR技术从苎麻细胞质雄性不育系、保持系和恢复系（简称“三系”）mtDNA中扩增目的基因片段;采用DNAWalking策略从3′端和5′端扩增基因片段的未知侧翼序列,分离完整的线粒体CoxⅡ、atpA基因;基于全基因序列和基因表达（RT-PCR法）分析这两个基因在苎麻“三系”间的差异。【结果】分离的苎麻CoxⅡ和atpA基因片段与GenBank中一些双子叶植物同类基因的同源性分别高达95%和97%以上,获得的CoxⅡ、atpA全基因包含了完整的开放阅读框。“三系”的CoxⅡ基因在mtDNA水平、转录水平、蛋白质水平上均无明显差异。雄性不育系atpA基因在mtDNA水平、氨基酸序列和蛋白质二级结构上与保持系和恢复系存在比较明显的差异;RT-PCR分析还表明,不育系atpA基因在现蕾期和开花后期的表达量明显低于可育系。【结论】CoxⅡ基因与苎麻CMS可能无关,而不育系atpA基因的序列变异和/或异常表达可能与苎麻CMS关系密切。

英文摘要：

[Objective] This study aimed at probing into the correlation of mitochondrial genes CoxⅡ and atpA with the cytoplasmic male sterility （CMS） in ramie [Boehmeria nivea （L.） Gaud,]. [Method] The CMS related CoxⅡ and aptA gene fragments were cloned from the mitochondrial DNA of ramie CMS line and its maintainer and restorer lines （fertile lines） by using PCR and degenerated primer strategy. The primers were designed according to the reserved sequences in the encoding region of mitochondrial genes CoxⅡ and atpA of some dicotyledons from GenBank. The complete CoxⅡ and atpA genes were obtained by means of amplifying the 3′ and 5′ end unknown sequences of these gene fragments using DNA Walking method. Based on the complete gene sequences and gene expression patterns （RT-PCR）, the differences of these two genes between ramie CMS line and the fertile lines were analyzed. [Result] The amplified CoxⅡ and atpA gene fragments showed 95% and 97% homology with the analogous genes from some dicotyledons. The complete Cox Ⅱ and atpA genes each had an intact open reading frame. The Cox Ⅱ gene showed no difference between ramie CMS line and fertile lines at the levels of mtDNA sequence, transcription and protein. However, compared to the fertile lines, atpA gene from CMS line showed obvious difference at the levels of mtDNA, amino acid sequence and the secondary structure of protein. And an abnormal low expression of atpA gene in CMS line at the budding stage and late-blooming stage was revealed by RT-PCR analysis. [Conclusion] The correlation of Cox Ⅱ gene with ramie CMS could be excluded, but the result suggested a close relationship of ramie CMS with the variation in DNA sequence and / or abnormality in expression of atpA gene in CMS line.