Roseobacter Cerasinus Sp. Nov., Isolated From A Fish Farm

An obligate aerobic and bacteriochlorophyll a-containing bacterium, designated strain A177(T), was isolated from a fish farm in Uwa Sea, Japan. Cells were Gram-stain-negative, coccoid- to oval-shaped, and showed no motility. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain A177(T) is a member of the genus Roseobacter and closely related to Roseobacter ponti MM-7(T) (97.8%), Roseobacter denitrificans OCh 114(T) (97.3%) and Roseobacter litoralis OCh 149(T) (97.3%). The G+C content of strain A177(T) was 61.0 mol%. The average amino acid identity values of the genome in strain A177(T) with those in R. denitrificans OCh 114(T )and R. litoralis OCh 149(T) were 73.26% (SD 16.46) and 72.63% (SD 16.76), respectively. The digital DNA-DNA hybridization values of strain A177(T) with the type strains R. denitrificans OCh 114(T) and R. litoralis OCh 149(T) were 18.70 and 18.50%, respectively. The dominant fatty acids (>10% of total fatty acids) of A177(T) were summed feature 8 (C-18:1 omega 7c and/or C-18:1 omega 6c) and saturated fatty acid C-16:0. The sole respiratory quinone was ubiquinone-10. The predominant polar lipids were phosphatidylcholine, phosphatidylglycerol and diphosphatidylglycerol. Based on the genetic and phenotypic data obtained herein, we conclude that strain A177(T) represents a new species of the genus Roseobacter, for which we propose the name Roseobacter cerasinus sp. nov.; the type strain is A177(T) (=DSM 110091(T) =NBRC 114115(T)).