Pelagibaca bermudensis gen. nov., sp nov., a novel marine bacterium within the Roseobacter clade in the order Rhodobacterales

A Gram-negative, chemoheterotrophic, facultatively anaerobic, slightly halophilic, oval-shaped marine bacterium, designated HTCC2601(T), was isolated from the western Sargasso Sea by high-throughput culturing involving dilution to extinction. Although the 16S rRNA gene sequence similarity between the isolate and Salipiger mucosus was 96-5%, phylogenetic analyses using different treeing algorithms clearly indicated that the strain forms a distinct lineage within a clade containing the recently classified genera Salipiger and Palleronia in the order Rhodobacterales of the Alphaproteobacteria. The DNA-DNA relatedness between strain HTCC2601(T) and & mucosus was 26-3%. Strain HTCC2601(T) utilized a wide range of carbohydrates, including hexose monomers, sugar alcohols, organic acids and amino acids, as sole carbon sources. The DNA G+C content of strain HTCC2601(T) was 65-4 mol%, and the predominant constituents of the cellular fatty acids were 18: 1 omega 7c (79.7%) and 11-methyl 18 : 1 omega 7c (7.5%). The strain differed from members of the closely related genera Salipiger and Palleronia in its morphological, biochemical and ecological characteristics. On the basis of the taxonomic data obtained in this study, a novel genus and species, Pelagibaca bermudensis gen. nov., sp. nov., is proposed; HTCC2601(T) (=KCTC 12554(T)=jCM 13377(T)) is the type strain of Pelagibaca bermudensis.