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

Abstract

Two aerobic, psychrohalotolerant, motile bacterial isolates, CK13^T 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 CK13^T and M. pontica and M. primoryensis were only 58 and 40%, respectively. The major fatty acids present in strain CK13^T were iso-C_16:0, C_16:0, C_16:1ω7c and C_18:1ω7c. 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 CK13^T to the genus Marinomonas. Phylogenetic analysis and phenotypic and genotypic distinctiveness confirmed that strains CK13^T 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 CK13^T (=MTCC 6645^T=DSM 16579^T=JCM 12522^T).