Dynamics of nuclear-mitochondrial interactions in the canola plant Brassica napus

油菜植物甘蓝型油菜中核-线粒体相互作用的动态

• 批准号: 7624-2010
• 负责人: Brown, Gregory
• 金额: $ 2.4万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=544427
• 关键词: Dynamics; nuclear; mitochondrial; interactions; canola

The genetic interaction between pathogens and host organisms has led to the concept of a genetic arms race: genes evolve in pathogens that allow them to evade host defenses, and in response genes evolve in hosts that allow them to resist such new pathogenic strains. Cytoplasmic male sterility (CMS) is a widespread trait among higher plants that results from the expression of novel open reading frames (ORFs) in mitochondrial DNA (mtDNA). In many cases, nuclear genes termed restorers-of-fertility (Rf) have been identified that suppress the CMS phenotype. Such restorer genes are specific for a particular form of CMS and function by down-regulating the expression of the novel, CMS-associated ORF. CMS can be viewed as a particularly interesting "intra-genomic" type of arms race: maternally inherited CMS-conferring mtDNAs spread in a population due to the selective advantage of not allocating resources into pollen production; as CMS individuals become more frequent, pollen becomes limiting, creating the selective pressure for evolution of new restorers. Studies from my laboratory over the last 15 year have revealed features of CMS / restorer gene systems of the canola plant Brassica napus that suggest these systems may provide a useful insight into this arms race. More recently, we discovered that ORF containing gene arrangements responsible for the two forms of B. napus CMS are present at substoichiometric levels in mitochondria in which they are not expected to occur, including mitochondria of one of the progenitor species of B. napus. In addition, we have now cloned and characterized one form of the Brassica nuclear restorer locus. The proposed studies build on this recent work and may allow us to obtain a comprehensive understanding of how CMS-restorer systems evolve. Specifically, we will determine if alteration mt genomic configurations can lead to amplification of the substoichiometric CMS-associated gene arrangements and male sterility; we will characterize the different forms of the restorer locus to gain insight into the molecular events by which the restorers evolved; and we will identify specific restorer genes and the molecules the proteins they encode interact with.

病原体和宿主生物之间的遗传相互作用导致了遗传军备竞赛的概念：病原体中的基因进化使它们能够逃避宿主防御，而作为回应，宿主中的基因进化使它们能够抵抗这种新的致病菌株。细胞质雄性不育（CMS）是高等植物中广泛存在的一种性状，其产生是由于线粒体DNA（mtDNA）中新的开放阅读框架（ORF）的表达。 在许多情况下，已鉴定出称为育性恢复因子（Rf）的核基因抑制CMS表型。这种恢复基因对特定形式的CMS具有特异性，并通过下调新的CMS相关ORF的表达来发挥功能。CMS可以被视为一种特别有趣的“基因组内”类型的军备竞赛：由于不将资源分配到花粉生产中的选择性优势，母系遗传的CMS赋予线粒体DNA在种群中传播;随着CMS个体变得更加频繁，花粉变得有限，为新恢复系的进化创造了选择压力。在过去的15年里，我的实验室的研究揭示了油菜植物甘蓝型油菜CMS /恢复基因系统的特征，这表明这些系统可能为这场军备竞赛提供有用的见解。最近，我们发现含有ORF的基因排列负责两种形式的B。napus CMS以亚化学计量水平存在于线粒体中，在线粒体中它们预期不会出现，包括B的祖先物种之一的线粒体。油菜。此外，我们现在已经克隆并表征了芸苔属核恢复基因座的一种形式。拟议的研究建立在最近的工作，并可能使我们能够获得一个全面的了解CMS恢复系统如何演变。具体来说，我们将确定是否改变mt基因组构型可以导致扩增的亚化学计量CMS相关的基因排列和雄性不育;我们将表征不同形式的恢复基因座，以深入了解恢复进化的分子事件;我们将确定特定的恢复基因和它们编码的蛋白质相互作用的分子。