Mitochondrial Alterations Associated with Cytoplasmic Male Sterility in Plant Development

几乎所有真核细胞的生长和分化都依赖于线粒体的代谢和能量产生。线粒体的正常功能涉及核和线粒体基因表达的综合系统。细胞质雄性不育是研究组织特异性线粒体功能和核因子在线粒体生物发生中的作用的一个系统。先前的研究已经确定了两个基因座atp6和atpA的变化，它们可能与小村萝卜的雄性不育有关。这些变化将通过以下实验进一步表征：在细胞器翻译、蛋白纯化和nh2末端测序中，将进行Western杂交分析，以研究：A) ATP6、ATPA和小谷特异性多肽ORF105的丰度；B) ATP6的nh2末端序列；C)核恢复位点对它们表达的影响。2. 生化和生理研究（例如测量atp酶活性、线粒体呼吸速率和膜电位）将对从正常、可育和不育的小村萝卜植株中分离的线粒体进行，以试图确定小村的线粒体在哪些过程中功能失调，以及是否与分子分析确定的假定改变有任何关联。3. 遗传学和分子方法（如重组线粒体基因组分析）将被用于试图建立线粒体序列改变与细胞质雄性不育之间的遗传因果关系。研究线粒体功能与细胞质雄性不育的关系，不仅有助于了解细胞的“动力源”——线粒体，还将揭示传粉机制发展的基本信息。

Growth and differentiation in nearly all eukaryotic cells depends on the metabolism and generation of energy by the mitochondrion. Proper functioning of the mitochondrion involves an integrated system of both nuclear and mitochondrial gene expression. Cytoplasmic male sterility is one system in which tissue-specific mitochondrial function and the role of nuclear factors on mitochondrial biogenesis can be studied. Previous studies have identifed alterations in two loci, atp6 and atpA, that may be involved with male steriltiy in Ogura radish. These alterations will be characterized further by the following experiments: 1. Western hybridization analysis, in organello translation, protein purification and NH2-terminal sequencing will be conducted to investigate: A) the abundance of the ATP6, ATPA and an Ogura- specific polypeptide, ORF105, B) the NH2-terminal sequence of ATP6, and C) the effect of nuclear restorer loci on their expression. 2. Biochemical and physiological studies (e.g. measurements of ATPase activities, mitochondrial respiratory rates and membrane potentials) will be conducted on mitochondria isolated from normal, and fertile and sterile Ogura radish plants in an attempt to identify in which processes Ogura mitochondria are dysfunctional and if there is any correlation with the putative alterations identified by molecular analysis. 3. Genetic and molecular approaches (e.g. analysis of recombinant mitochondrial genomes) will be utilized in an attempt to establish a genetic, casual relationship between altered mitochondrial sequences and cytoplasmic male sterility. The relationship between mitochondrial function and cytoplasmic male sterility not only allows an understanding of the cells "power plant", the mitochondria, but also will reveal basic information about the development of the pollination mechanism.