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新陈代谢和能量生成。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线粒体组织特异性功能和核因子在线粒体生物发生中的作用的系统。以前的研究已经确定了两个基因座atp6和atpa的变化，这可能与小仓萝卜的雄性不育有关。这些变化将通过以下实验得到进一步的表征：1.通过Western杂交分析、细胞器翻译、蛋白质纯化和NH2末端测序，将研究：A)ATP6、ATPA和Ogura特异性多肽ORF105的丰度；B)ATP6的NH2末端序列；以及C)核恢复基因座对其表达的影响。2.将对正常、可育和不育的Ogura萝卜植株的线粒体进行生化和生理学研究(如ATPase活性、线粒体呼吸速率和膜电位的测量)，试图确定Ogura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变化有关。3.将利用遗传和分子方法(例如，重组线粒体基因组的分析)，试图在线粒体序列改变和细胞质雄性不育之间建立遗传的、随意的关系。线粒体功能与细胞质雄性不育之间的关系不仅有助于了解细胞的动力装置--线粒体，而且还将揭示授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.