Most of the biological diversity in eukaryotes (organisms with distinct nuclei) is in the form of microscopic species and, when compared to other eukaryotes (plants, animals and fungi), is less well-studied in terms of morphological characterisitics, evolutionary relationships among species, and genetic variation. This relative lack of information on microbial eukaryotes not only has consequences for our understanding of all biodiversity on Earth, but also how we interpret cellular and evolutionary biology in the broadest sense. This research will advance our knowledge of a major evolutionary group (clade) of microbial eukaryotes that comprise the Stramenopila, Alveolata and Rhizaria, (SAR). SAR is a major clade of diverse microscopic eukaryotes that was recently identified by evolutionary analyses and additional data have robustly supported SAR as an independent evolutionary lineage. This discovery is forcing a re-evaluation of the evolution of several eukaryotic traits, most notably photosynthesis. Within SAR there are many diverse lineages but genetic data are rare and concentrated in only a few lineages: Apicomplexa (e.g. malarial parasites), omycetes (e.g. parasite water molds) and diatoms (e.g. ecologically important phytoplankton). This project proposes to increase the number of SAR species with genetic data as well as massively increase the amount of genetic data collected per species. Organisms used for genomic data will be imaged and will be integrated to the Encyclopedia of Life (EOL) to provide a comprehensive resource on microbial eukaryotic diversity.
Despite their global ecological importance, fewer than 50% of all SAR clades are represented by even a single genome in public databases. The work proposed here would add at least 250 novel genomic-scale datasets (transcriptomes, draft genomes, single-cell amplified genomes), focused primarily on capturing diversity within SAR. These datasets will be made publicly available, substantially increasing our understanding of the evolution of these organisms. The application of both established phylogenomic and emerging similarity network methods will enable a multi-layered analysis that will provide new information for evolutionary analyses of these organisms. This will include: 1) diversity discovery using targeted environmental 18S surveys coupled with high-throughput FlowCam imaging; 2) high-throughput transcriptomic sequencing; and 3) single cell genomics of unculturable taxa. Phylogenetic analyses will capture the genetic mosaics that underlie the early evolution within SAR. Beyond the increase in genome scale resources from diverse members of the SAR clade, the proposed work will generate image data layers and integrate these with other images from the literature in EOL. Undergraduates, graduate students and postdoctoral fellows will be trained in cutting edge techniques and will provide a workshop for teacher training in microscopy. This project will increase diversity of participants by recruiting students from underrepresented groups and develop of a high school curriculum on the microbial tree of life.
