Comparative organellar genomics in heterotrophic plants

一些植物从普通的绿色植物那里偷取营养和/或水，结果减少或完全失去了光合作用的能力。我们研究了各种所谓的异养植物（通常称为寄生植物）的质体基因组。对整个营养谱上的质体进行比较分析，从自养到混合养再到完全异养，将使我们能够评估在光合作用完全丧失之前基因组变化的程度，并剖析质体代谢功能对质体施加的进化压力。许多异养植物群是从它们各自的光合亲戚中分离出来的。我们在这个建议中利用的基本思想是，每一个异养生物谱系都代表了一个独立的自然遗传实验，其质体和基因在宽松的功能约束下进化；因此，每一个都是研究基因组功能和进化的独特机会。考虑到逆向遗传方法在这一系统中的困难甚至不可能，对多种天然质体“突变体”的研究将有助于我们更深入地了解光合作用、其分子组成及其相互作用。

Some plants steal nutrients and/or water from regular green plants and consequently have reduced or completely lost their ability to photosynthesize. We study plastid genomes in a variety of these so-called heterotrophic plants (commonly known as parasitic plants). Comparative analyses of the plastomes along the full trophic spectrum, from autotrophy to mixotrophy to full heterotrophy, will allow us to assess the degree to which genomic changes take place prior to complete loss of photosynthesis, and to dissect the evolutionary pressures on plastomes exerted by other plastid metabolic functions. Many groups of heterotrophic plants arose separately from their respective photosynthetic relatives. The basic idea we take advantage of in this proposal is that each of those lineages of heterotrophs represents an independent natural genetic experiment whose plastids and genes have evolved under relaxed functional constraints; therefore, each represents a unique opportunity to study genome function and evolution. Given the difficulties or even the impossibility of reverse genetic approach in this system, study of multiple natural plastid 'mutants' will contribute to our deeper understanding of photosynthesis, its molecular components, and their interaction.