Roseovarius atlanticus sp. nov., isolated from surface seawater

A taxonomic study was carried out on strain R12B T , which was isolated from surface seawater of the Atlantic Ocean. The bacterium was observed to be rod-shaped, Gram-stain-negative, oxidase-positive and weakly positive for catalase. Growth was observed at salinities of 0.5-15 % and at temperatures of 4-45 °C. The isolate was incapable of nitrate reduction and hydrolysis of gelatin, Tween 80 and aesculin. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain R12B T belonged to the genus Roseovarius , with highest sequence similarity to Roseovarius indicus B108 T (97.2 % 16S rRNA gene sequence similarity), followed by Roseovarius halotolerans HJ50 T (96.8 %); other species of genus Roseovarius shared 93.0-96.2 % sequence similarities. The DNA-DNA hybridization estimate value between strain R12B T and R. indicus B108 T was 23.2 ± 2.4 %. The average nucleotide identity between strain R12B T and R. indicus B108 T was 77.1 %. The principal fatty acids were summed feature 8 (C 18 : 1 ω7 c /ω6 c ) and C 16 : 0 . The G+C content of the chromosomal DNA was 63.6 mol%. The respiratory quinone was determined to be Q-10. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, two aminolipids, two phospholipids and some unidentified lipids were present. The combined genotypic and phenotypic data show that strain R12B T represents a novel species of the genus Roseovarius , for which the name Roseovarius atlanticus sp. nov. is proposed, with the type strain R12B T ( = MCCC 1A09786 T  = KCTC 42506 T ).