Center for Plant Science Innovation, University of Nebraska, Lincoln, Nebraska 68588-0660, USA.
Plant Physiol. 2010 Apr;152(4):1960-70. doi: 10.1104/pp.109.152827. Epub 2010 Feb 5.
Three nuclear genes involved in plant mitochondrial recombination surveillance have been previously identified. Simultaneous disruption of two of these genes, MutS Homolog1 (MSH1) and RECA3, results in extensive rearrangement of the mitochondrial genome and dramatic changes in plant growth. We have capitalized on these changes in mitochondrial genome organization to understand the role mitochondria play in plant cellular and developmental processes. Transcript profiling of the double mutants grown under normal conditions revealed differential regulation of numerous nuclear genes involved in stress responses together with increased levels of polyadenylated mitochondrial transcripts. We show that extensive rearrangement of the mitochondrial genome in Arabidopsis (Arabidopsis thaliana) directly elicits physiological stress responses in plants, with msh1 recA3 double mutants exhibiting enhanced thermotolerance. Likewise, we show that mitochondrial transcriptional changes are associated with genome recombination, so that differential gene modulation is accomplished, at least in part, through altered gene copy number.
先前已经鉴定出三个参与植物线粒体重组监测的核基因。这两个基因（MutS Homolog1（MSH1）和 RECA3）的同时缺失会导致线粒体基因组的广泛重排，并显著改变植物的生长。我们利用线粒体基因组结构的这些变化来了解线粒体在植物细胞和发育过程中的作用。在正常条件下生长的双突变体的转录谱分析显示，许多参与应激反应的核基因的表达水平存在差异，同时多聚腺苷酸化的线粒体转录本水平升高。我们表明，拟南芥线粒体基因组的广泛重排直接引发植物的生理应激反应，msh1 recA3 双突变体表现出增强的耐热性。同样，我们表明线粒体转录变化与基因组重组有关，因此差异基因调控至少部分是通过改变基因拷贝数来实现的。
