Ruegeria pelagia sp. nov., isolated from the Sargasso Sea, Atlantic Ocean.

Gram-negative, facultatively aerobic, chemoheterotrophic, short rod-shaped marine bacterial strains HTCC2662(T) and HTCC2663, isolated from the Sargasso Sea by using a dilution-to-extinction culturing method, were investigated to determine their taxonomic position. Characterization of the two strains by phenotypic and phylogenetic analyses revealed that they belonged to the same species. The DNA G+C content of strain HTCC2662(T) was 58.4 mol% and the predominant cellular fatty acids were C(18 : 1) omega 7c (52.5 %), C(16 : 0) 2-OH (13.5 %) and C(18 : 1) 11-methyl omega 7c (12.2 %). Phylogenetic analysis of the 16S rRNA gene sequences showed that the strains represented a distinct line of descent within the genus Ruegeria, with highest sequence similarities to Ruegeria atlantica DSM 5823(T) (97.2 %), Ruegeria lacuscaerulensis DSM 11314(T) (96.5 %) and Ruegeria pomeroyi DSM 15171(T) (95.6 %). Several phenotypic characteristics, including facultatively requiring NaCl and oxygen for growth, together with the cellular fatty acid composition, differentiated strain HTCC2662(T) from other members of the genus Ruegeria. Based on phenotypic, chemotaxonomic and phylogenetic traits, it is suggested that strains HTCC2662(T) and HTCC2663 represent a novel species of the genus Ruegeria, for which the name Ruegeria pelagia sp. nov. is proposed. The type strain is HTCC2662(T) (=KCCM 42378(T)=NBRC 102038(T)).