En-Gen: Proteomics Directed Environmental Genomics: Identifying in Situ Physiological Diversity of Cyanobacterial Nutrient Utilization in the South Atlantic Ocean

University Of Washington, Seattle WA

Investigators

Abstract

The unicellular marine cyanobacteria Prochlorococcus and Synechococcus account for up to 50% of primary productivity at mid latitudes in the world?s oceans. The phylogeny, physiology, and biogeography of these cyanobacteria suggest that they are comprised of several closely related ecotypes. These light adapted lineages and sublineages differ in vertical and latitudinal distributions, although the physiological adaptations that drive their distributions are not yet well understood. Comparative genomic studies of both Prochlorococcus and Synechococcus suggest that the lateral transfer of nutrient uptake and stress response genes may be driving genetic microdiversity and niche partitioning in the marine environment. Because proteins, rather than genes, determine an organism's phenotype under a defined set of conditions, proteomic approaches are ideal for in situ verification of microbial processes. This project proposes to apply a proteomic and genomic survey of the South Atlantic photic zone to explore the role of nutrient and stress response genes in shaping community structure of marine cyanobacteria. In addition to identifying actively expressed genes within diverse gene families, results from this project will help clarify relationships between nutrient dynamics and bacterioplankton community structure. Further, marine cyanobacteria provide a model system for using environmental genomic and proteomic approaches to investigate mechanisms driving niche differentiation. The project will also involve young investigators in the ocean sciences by preparing them to take advantage of genomic approaches. A post-doctoral associate and several undergraduate students will also be actively involved in the research program. Data from this project will be used to develop a computer laboratory module for a graduate course in environmental genomics taught at the University of Washington, and support from this proposal will also allow expansion of a proteomics component in the summer Microbial Oceanography course at the Bermuda Institute for Ocean Science.