Roseovarius atlanticus sp. nov., isolated from surface seawater

A taxonomic study was carried out on strain R12BT, 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 R12BT belonged to the genus Roseovarius, with highest sequence similarity to Roseovarius indicus B108T (97.2 % 16S rRNA gene sequence similarity), followed by Roseovarius halotolerans HJ50T (96.8 %); other species of genus Roseovarius shared 93.0–96.2 % sequence similarities. The DNA–DNA hybridization estimate value between strain R12BT and R. indicus B108T was 23.2 ± 2.4 %. The average nucleotide identity between strain R12BT and R. indicus B108T was 77.1 %. The principal fatty acids were summed feature 8 (C18 : 1ω7c/ω6c) and C16 : 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 R12BT represents a novel species of the genus Roseovarius, for which the name Roseovarius atlanticus sp. nov. is proposed, with the type strain R12BT ( = MCCC 1A09786T = KCTC 42506T).