Stoichiometric Shifting of the Plant Mitochondrial Genome

植物线粒体基因组已经进化出影响其结构和表达的几个显著特征。 其中之一是亚基因组DNA分子以明显不同的拷贝数维持。 将使用菜豆细胞质雄性不育系统研究植物线粒体基因组内拷贝数的基因组移位和亚化学计量DNA分子的保留的现象。 该奖项将支持两名研究生完成博士学位。论文研究本课题的两个方面。 第一个将调查线粒体基因组中的基因组移位的生理意义，通过检查移位对交叉相容性的影响，温度对移位过程的影响，以及线粒体基因组被保护免受移位的植物组织。 第二个学生将研究线粒体不育序列pvs-orf 239的表达及其对转换过程的影响。 这将包括研究ORF 239产物从细胞外基质向细胞周边的输出;这些特殊的研究将在用pvs-orf 239序列转化的酵母中进行。这些研究，通过利用普通菜豆系统特有的特征，解决与所有高等植物相关的生物学现象，并且应该提供用于定向操纵植物线粒体基因型的策略。

The plant mitochondrial genome has evolved several distinguishing features that influence its structure and expression. One of these is the maintenance of subgenomic DNA molecules at markedly different copy numbers. The phenomenon of genomic shifts in copy number and the retention of substoichiometric DNA molecules within the plant mitochondrial genome will be investigated using the cytoplasmic male sterility system in common bean. This award will support two graduate students to complete their Ph.D. thesis research in two areas of this topic. The first will investigate the physiological implications of genomic shifts in the mitochondrial genome by examining the effects of shifting on cross-compatibility, the influence of temperature on the shifting process, and the plant tissues in which the mitochondrial genome is protected from shifting. The second student will investigate the expression of the mitochondrial sterility sequence, pvs-orf239, and its influence on the shifting process. This will include investigation of the export of the ORF239 product from the mitochondrion to the periphery of the cell; these particular studies will be carried out in yeast transformed with the pvs-orf239 sequence.These investigations, through taking advantage of features special to the common bean system, address biological phenomena relevant to all higher plants, and should provide strategies for directed manipulation of the plant mitochondrial genotype.