Roseovarius halocynthiae sp nov., isolated from the sea squirt Halocynthia roretzi

A Gram-negative, motile, ovoid- to rod-shaped bacterial strain, designated MA1-10(T), was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea. Strain MA1-10(T) grew optimally at pH 7.0-8.0, at 30 degrees C and in the presence of 2% (w/v) NaCl. In the neighbour-joining phylogenetic tree based on 16S rRNA gene sequences, strain MA1-10(T) clustered with Roseovarius crassostreae CV919-312(T), with which it exhibited 97.1% sequence similarity, at a bootstrap resampling value of 96.20%. It exhibited 93.3-95.8% 16S rRNA gene sequence similarity to the type strains of other recognized Roseovarius species. Strain MA1-10(T) contained Q-10 as the predominant ubiquinone and C-18:1 omega 7c as the major fatty acid, which is consistent with data for the genus Roseovarius. The major polar lipids were phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, an unidentified aminolipid and an unidentified lipid. The DNA G+C content of strain MA1-10(T) was 55.4 mol%. Mean DNA DNA relatedness between strain MA1-10(T) and R. crassostreae DSM 16950(T) was 13%. Differential phenotypic properties, together with phylogenetic and genetic distinctiveness, demonstrated that strain MA1-10(T) could be distinguished from all recognized Roseovarius species. On the basis of the data presented, strain MA1-10(T) is considered to represent a novel species of the genus Roseovarius, for which the name Roseovarius halocynthiae sp. nov. is proposed; the type strain is MA1-10(T) (=KCTC 23462(T)=CCUG 60745(T)).