Investigating recurrent cooption of mitochondrial cytochrome c maturation systems in Archaeplastida

趋同进化是同一特征在不同物种中的独立起源。通常，融合特征的适应性益处是显而易见的，例如鸟类、蝙蝠和昆虫的动力飞行的融合进化。然而，并不是所有的收敛进化都有明显的优势。例如，c型细胞色素的翻译后修饰对于它们作为线粒体电子传输链的正确功能是必不可少的，线粒体电子传输链产生并调节细胞内的能量流动。两种不同的生化途径被用来实现这种修饰，许多物种在这两种不同的途径之间进行了一致的切换。然而，这两条途径都实现了相同的目标，因此这种途径转换的进化优势尚不清楚。本项目将研究植物和绿藻中的众多收敛途径开关。该项目将结合分子生物学、基因工程、植物生长发育分析和计算生物学来评估这种途径转换的机制和进化重要性。项目参与者将接受基因组研究方面的高级培训。研究成果将通过期刊文章和会议报告进行传播。该项目将使用转基因方法和功能分析来评估线粒体定位，评估基因敲除/基因敲除系，并通过对一种关键酶的转化拯救来恢复功能。基于比较基因组学的预期是，这种酶的获得使不同植物和藻类的趋同途径转换成为可能。该项目还将使用转基因技术在一个模型植物中创造一个人工系统开关。这些转基因植物将使用代谢组学、功能分析和高通量表型分析进行评估，以评估这种转换的潜在适应或有害影响。系统发育学和比较基因组学将通过探索真核生物进化过程中途径开关的数量，评估是否存在促进这种开关的其他替代途径，以及评估水平转移在真核生物之间传播替代途径的作用，来评估细胞色素c在植物和真核生物中成熟的宏观进化模式。这一结果将扩大对在没有明显适应效益的情况下促进收敛进化的过程和影响的理解，这与其他著名的并行进化的例子形成对比，对该方案进行了共同审查，并将由分子和细胞生物科学司的遗传机制集群和环境生物学司的进化过程集群共同资助。这一奖项反映了NSF的法定使命，通过使用基金会的学术价值和更广泛的影响审查标准进行评估，被认为是值得支持的。

Convergent evolution is the independent origin of the same feature in different species. Often, the adaptive benefit of a convergent feature is apparent, such as the convergent evolution of powered flight in birds, bats and insects. However, not all cases of convergent evolution have an obvious advantage. For example, the post-translational modification of c-type cytochromes is essential for their proper function as part of the mitochondrial electron transport chain, which produces and regulates energy flow in cells. Two distinct biochemical pathways are used to achieve this modification, and many species have convergently switched between these two distinct pathways. Yet, both pathways achieve the same goal, so the evolutionary advantage of this pathway switch is unknown. This project will investigate the numerous convergent pathway switches in plants and green algae. The project will use a combination of molecular biology, genetic engineering, plant growth and development assays, and computational biology to assess the mechanisms and evolutionary importance of this pathway switch. Project participants will receive advanced training in genomics research. Research results will be disseminated through journal articles and conference presentations. Outreach experiences will include public presentations, demonstrations, and hands-on activities that educate the public on plant science research and applications.The project will use transgenic approaches and functional assays to assess mitochondrial localization, evaluate knock out/down lines, and restore function via transformation rescue of a key enzyme. The expectation, based on comparative genomics, is that the gain of this enzyme has enabled the convergent pathway switch in diverse plants and algae. The project will also use transgenics to create an artificial system switch in a model plant. These transgenic plants will be assessed using metabolomics, functional assays, and high-throughput phenotyping to evaluate the potential adaptive or detrimental effects of this switch. Phylogenetics and comparative genomics will be used to evaluate the macroevolutionary patterns of cytochrome c maturation across plants and eukaryotes by exploring the number of pathway switches during eukaryotic evolution, evaluating whether other alternate pathways exist to facilitate the switch, and assessing the role of horizontal transfer in spreading alternative pathways among eukaryotes. The results will broaden understanding of the processes and influences that promote convergent evolution under a scenario where there is no obvious adaptive benefit, which contrasts with other well-known examples of parallel evolution for which the adaptive benefit is obvious.This proposal was co-reviewed and will be co-funded by the Genetic Mechanisms Cluster in the Division of Molecular and Cellular Biosciences and by the Evolutionary Processes Cluster of the Division of Environmental Biology. Funding was also provided by the Established Program to Stimulate Competitive Research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.