Genomic and proteomic insights into glaucophyte plastids

光合作用是一个核心的生理过程，占了地球上大部分的初级生产和氧气产生。光合作用大约在30亿年前由蓝藻进化而来。在这一事件发生20亿年之后，某些真核细胞通过细胞内共生（内共生）招募了一些蓝藻，并进化成藻类和植物的质体。据推测，现存的藻类（蓝藻、红藻和绿藻，包括陆生植物）携带被两层膜包围的质体，并正式命名为植物，是由共同祖先携带直接来自内共生蓝藻（原生质体）的质体的后代。验证植物共同起源的假设对于理解第一个光合真核生物的出现是至关重要的。研究这一假设的一个途径是通过对不同植物谱系的遗传和蛋白质谱的比较研究。在这方面，绿藻和陆地植物已经得到了深入的研究，但红藻和蓝藻却不是这样。我的研究调查了来自蓝藻的质体的基因组和功能方面，这可能代表了植物中最早的分化谱系。因此，研究苔藓植物对了解植物的起源和多样性具有重要意义。我的项目包括三个具体目标。1)比较转录组学。来自不同蓝藻植物的表达基因（mrna）将被测序和分析。我们将研究编码蛋白，重点是质体靶向成分。2)质体基因组学。我们将对不同蓝藻物种的质体基因组进行测序。我们将分析序列数据，以探索基因内容，基因组结构和多样性的群体。3)质体蛋白质组学。我们将鉴定不同蓝藻的质体蛋白集合。我们将把这些数据与其他植物的相应数据集和我们的转录组数据进行比较。我们将确定植物之间共享的质体蛋白核心成分和独特的蛋白质特征。总的来说，来自这三个目标的数据将测试植物质体的假定共同起源和蓝藻植物的早期分化。

Photosynthesis is a central physiological process that accounts for most of primary production and oxygen generation in the planet. Photosynthesis evolved in cyanobacteria around three billion years ago. Two billion years after this event some cyanobacteria were recruited via intracellular symbiosis (endosymbiosis) by certain eukaryote cells and evolved into the plastids of algae and plants. It has been hypothesized that extant algae (glaucophytes, red and green algae, including land plants) bearing plastids surrounded by two membranes, and formally named Plantae, are descended from common ancestors harboring plastids derived directly from endosymbiotic cyanobacteria (primary plastids). Testing this hypothesis of common origin of Plantae is critical to understand the emergence of the first photosynthetic eukaryotes. One avenue to study this hypothesis is through comparative studies of genetic and protein repertoires from different Plantae lineages. Green algae and land plants have been thoroughly studied in this respect, but this is not the case for red algae and glaucophytes. My research investigates genomic and functional aspects of plastids from glaucophytes, which likely represent the earliest diverging lineage within Plantae. Thus, the study of glaucophytes is important for understanding the origin and diversification of Plantae. My project comprises three specific objectives. 1) Comparative transcriptomics. Pools of expressed genes (mRNAs) from different glaucophytes will be sequenced and profiled. We will study encoded proteins with emphasis on the plastid-targeted component. 2) Plastid genomics. We will sequence plastid genomes of diverse glaucophyte species. We will analyze sequence data to explore gene content, genome architecture and diversity within the group. 3) Plastid proteomics. We will identify plastid protein collections of diverse glaucophytes. We will compare these data with corresponding datasets from other Plantae and our transcriptome data. We will identify both plastid protein core components shared between Plantae and unique protein traits. In toto, data from the three objectives will test both the presumed common origin of Plantae plastids and the early divergence of glaucophytes.