Roseovarius indicus sp. nov., isolated from deep-sea water of the Indian Ocean

A taxonomic study was carried out on a novel bacterial strain, designated B108(T), which was isolated from a polycyclic aromatic hydrocarbon (PAH)-degrading consortium, enriched from deep-sea water of the Indian Ocean. The isolate was Gram-reaction-negative, rod-shaped and non-motile. Growth of strain B108(T) was observed in 1-15 % (w/v) NaCl and at 10-39 °C and it was unable to degrade Tween 80 or gelatin. 16S rRNA gene sequence comparisons showed that strain B108(T) was most closely related to Roseovarius halotolerans HJ50(T) (97.1 % sequence similarity), followed by Roseovarius pacificus 81-2(T) (96.6 %) and Roseovarius aestuarii SMK-122(T) (95.2 %); other species shared <95.0 % sequence similarity. DNA-DNA hybridization tests showed that strain B108(T) had a low DNA-DNA relatedness to R. halotolerans HJ50(T) and R. pacificus 81-2(T) (48±4 % and 44±5 %, respectively). The predominant fatty acids were C₁₆:₀, C₁₆:₀ 2-OH, summed feature 8 (C₁₈:₁ω7c/ω6c) and C₁₉:₀ω8c cyclo, which accounted for 84.2 % of the total cellular fatty acids. The G+C content of the chromosomal DNA was 63.6 mol%. The major respiratory quinone was ubiquinone 10 (Q10). Phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and some unidentified compounds were detected. These characteristics were in good agreement with those of members of the genus Roseovarius. The pufLM gene was also detected. According to its morphology, physiology, fatty acid composition and phylogenetic position based on 16S rRNA sequence data, the novel strain most appropriately belongs to the genus Roseovarius but can be readily distinguished from known species of this genus. Therefore, strain B108(T) represents a novel species, of the genus Roseovarius, for which the name Roseovarius indicus sp. nov. is proposed. The type strain is B108(T) ( = 2PR52-14(T)  = CCTCC AB 208233(T)  = LMG 24622(T)  = MCCC 1A01227(T)).