Marinomonas polaris sp. nov., a psychrohalotolerant strain isolated from coastal sea water off the subantarctic Kerguelen islands

Abstract

Two aerobic, psychrohalotolerant, motile bacterial isolates, CK13T and CK16, isolated from sea-water samples collected off the subantarctic Kerguelen island, were characterized by using a polyphasic taxonomic approach. On the basis of 16S rRNA gene sequence data, the strains were 99·6 % similar and exhibited 93–97 % similarity with the seven recognized species of Marinomonas. The most closely related species were Marinomonas pontica and Marinomonas primoryensis, with 97 and 96 % similarity at the 16S rRNA gene sequence level, respectively. DNA–DNA hybridization values between strain CK13T and M. pontica and M. primoryensis were only 58 and 40 %, respectively. The major fatty acids present in strain CK13T were iso-C16 : 0, C16 : 0, C16 : 1 ω7c and C18 : 1 ω7c. The DNA G+C content of strain CK13T was 41·2 mol%. Phosphatidylethanolamine and phosphatidylglycerol were identified as the predominant phospholipids. All the above characteristics support the affiliation of strain CK13T to the genus Marinomonas. Phylogenetic analysis and phenotypic and genotypic distinctiveness confirmed that strains CK13T and CK16 are members of a novel species of the genus Marinomonas, for which the name Marinomonas polaris sp. nov. is proposed. The type strain is CK13T (=MTCC 6645T=DSM 16579T=JCM 12522T).