Genome analysis of the proteorhodopsin-containing marine bacterium Polaribacter sp. MED152 (Flavobacteria)

Abstract

Analysis of marine cyanobacteria and proteobacteria genomes has provided a profound understanding of the evolution of photosynthesis and the molecular ecology of marine bacteria. However, because microeukaryotes appear to be the main primary producers and the major drivers of global biogeochemical cycles, their genomic data are critical for understanding global marine processes. Here we report the complete genome sequence and annotation of Ostreococcus lucimarinus, a coccoid green alga with a cell diameter of approximately 1 microm, as well as a comparative genomic analysis with the related Ostreococcus tauri. At 13.2 Mb, O. lucimarinus has the smallest nuclear genome of any photosynthetic eukaryote sequenced to date. We find a striking conservation of synteny between O. lucimarinus and O. tauri, and a dramatic reduction in genes coding for cell wall biosynthesis and related processes. The complement of genes potentially involved in adaptation to the marine environment is expanded relative to fresh-water organisms. By comparing these two Ostreococcus genomes with other eukaryotic algae we identify minimal sets of genes required for flagella and centrioles, and for the light-harvesting and carbon fixation processes of green algae.

Javier del Campo

Group Leader

My research aims at understanding the global diversity and distribution of eukaryotic and prokaryotic microbes employing curated phylogenetic frameworks focusing on novel environmental taxa.