Genomic and proteomic insights into glaucophyte plastids

光合作用是一个中心的生理过程，占大多数的初级生产和氧气的产生在地球上。光合作用在大约30亿年前在蓝藻中进化出来。在这一事件发生20亿年后，一些蓝藻通过细胞内共生（内共生）被某些真核生物细胞招募，并进化成藻类和植物的质体。已经假设携带由两层膜包围的质体的现存藻类（蓝绿藻、红藻和绿色藻类，包括陆地植物），并且正式命名为植物，是从携带直接源自内共生蓝藻的质体（初级质体）的共同祖先传下来的。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至关重要。研究这一假说的一个途径是通过比较研究不同植物谱系的遗传和蛋白质库。绿色藻类和陆地植物在这方面已经得到了彻底的研究，但红藻和蓝绿藻的情况并非如此。我的研究调查的基因组和功能方面的质体从glaucophytes，这可能代表了最早的分歧谱系内植物。因此，研究灰绿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。将对来自不同蓝绿藻的表达基因（mRNA）的序列进行测序和分析。我们将研究编码的蛋白质，重点是质体靶向成分。2)质体基因组学。我们将对不同的蓝绿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，基因组结构和组内的多样性。3)质体蛋白质组学。我们将鉴定不同蓝绿藻的质体蛋白质集合。我们将这些数据与来自其他植物的相应数据集和我们的转录组数据进行比较。我们将确定植物和独特的蛋白质性状之间共享的质体蛋白质核心成分。总的来说，来自三个目标的数据将测试植物质体的假定共同起源和蓝绿藻的早期分歧。

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.