Candidatus Pelagibacter sp. HIMB1321 Genome sequencing

The heterotrophic alphaproteobacterial clade SAR11 accounts for approximately 25% to 50% of microbial plankton cells in the ocean surface layer, making it key to understanding the marine carbon cycle. Genome streamlining has been implicated as an important factor in the evolution of SAR11 genomes. Ecological and genomic evidence suggest that at least three SAR11 ecotypes, each with a different seasonal and spatial distribution pattern, occupy the temperate ocean surface layer. Analysis of sequenced genomes aims to develop evolutionary models for the dominance of this clade and to reveal what adaptations, particularly organic carbon substrate specificities, distinguish the SAR11 ecotypes.