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 : 1ω7c/ω6c) 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).