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

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(16:1)omega 7c and C(18:1)omega 7c. The DNA G + C content of strain CK13(T) was 41.2 mol%. Phosphaticlylethanolamine and phosphaticlylglycerol were identified as the predominant phospholipids. All the above characteristics support the affiliation of strain CK13(T) to the genus Marinamonas. 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)).