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

A Gram-negative, non-motile, rod-shaped bacterial strain, designated MA1-6(T), was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea, and was characterized to determine its taxonomic position. Strain MA1-6(T) grew optimally at pH 7.0-8.0, at 30 degrees C and in the presence of 2-3% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain MA1-6(T) fell within the clade comprising Ruegeria species and exhibited 95.3-96.5% similarity to the type strains of recognized Ruegeria species. Strain MA1-6(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 Ruegeria species. The major polar lipids detected in strain MA1-6(T) and Ruegeria atlantica KCTC 12424(T) were phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid and an unidentified lipid. The DNA G+C content of strain MA1-6(T) was 58.6 mol%. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain MA1-6(T) can be distinguished from recognized Ruegeria species. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain MA1-6(T) is considered to represent a novel species of the genus Ruegeria, for which the name Ruegeria halocynthiae sp. nov. is proposed; the type strain is MA1-6(T) (=KCTC 23463(T)=CCUG 60744(T)).