Comparative genomic and functional approaches for investigating biology and evolution of heterotrophic plants

研究异养植物生物学和进化的比较基因组和功能方法

• 批准号: RGPIN-2021-02689
• 负责人: Stefanovic, Sasa
• 金额: $ 3.42万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=746012
• 关键词: Comparative; genomic; functional; approaches; investigating

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) as well as their interaction with other plant genomes. 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 and 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.       We will conduct an extensive study of organellar genome content, sequence, and expression patterns in heterotrophic plants and their closest autotrophic relatives in order to ultimately be able to integrate genomic, functional, and evolutionary data. This will be achieved by sequencing transcriptomes and/or whole genomes in a large number of heterotrophic plants, comparison of results found in evolutionarily distinct groups, and doing so in a well-established historical context. These new next-generation sequencing data will allow us to test the predictions that some genomic changes precede the evolution of full-blown heterotrophy, that there are limits to how reduced plastomes can be, as well as to ascertain whether the patterns of plastome evolution are gradual or stepwise (punctuated). This investigation will complement other studies being performed in closely related areas and will impact the fields of genomics, molecular evolution, genetic engineering, physiology, and systematics.

一些植物从普通绿色植物中窃取营养和/或水分，因此减少或完全失去了光合作用的能力。我们研究了这些所谓的异养植物（通常称为寄生植物）中的质体基因组以及它们与其他植物基因组的相互作用。比较分析的质体沿着全营养谱，从自养，混合营养，以充分异养，将使我们能够评估的程度，基因组的变化发生之前，完全丧失光合作用，并剖析其他质体代谢功能所施加的质体的进化压力。许多类群的异养植物分别从它们各自的光合亲戚中产生。我们在这个提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，其质体和基因在放松的功能限制下进化，因此，每一个都代表了研究基因组功能和进化的独特机会。鉴于在这一系统中反向遗传方法的困难，甚至是不可能的，多个天然质体“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，以及它们之间的相互作用。 我们将进行广泛的研究细胞器基因组的内容，序列和表达模式在异养植物和它们最接近的自养亲属，以最终能够整合基因组，功能和进化数据。这将通过对大量异养植物中的转录组和/或全基因组进行测序，比较在进化上不同的组中发现的结果，并在完善的历史背景下进行。这些新的下一代测序数据将使我们能够测试一些基因组变化先于全面异养进化的预测，减少质体的数量是有限的，以及确定质体进化的模式是渐进的还是逐步的（间断的）。这项研究将补充在密切相关的领域正在进行的其他研究，并将影响基因组学，分子进化，遗传工程，生理学和系统学领域。