Roseibacterium beibuensis sp. nov., a Novel Member of Roseobacter Clade Isolated from Beibu Gulf in the South China Sea

A novel aerobic, bacteriochlorophyll-containing bacteria strain JLT1202r^T was isolated from Beibu Gulf in the South China Sea. Cells were gram-negative, non-motile, and short-ovoid to rod-shaped with two narrower poles. Strain JLT1202r^T formed circular, opaque, wine-red colonies, and grew optimally at 3–4?% NaCl, pH 7.5–8.0 and 28–30?°C. The strain was catalase, oxidase, ONPG, gelatin, and Voges–Proskauer test positive. In vivo absorption spectrum of bacteriochlorophyll a presented two peaks at 800 and 877?nm. The predominant cellular fatty acid was C_18:1 ω7c and significant amounts of C_16:0, C_18:0, C_10:0 3-OH, C_16:0 2-OH, and 11-methyl C_18:1 ω7c were present. Strain JLT1202r^T contained Q-10 as the major respiratory quinone and the genomic DNA G+C content was 76.3?mol%. Phylogenetic analysis based on 16S rRNA gene sequences of various species with validly published names showed that strain JLT1202r^T fell within the genus Roseibacterium, family Rhodobacteraceae, sharing the highest similarity with Roseibacterium elongatum OCh 323^T (97.9?% similarity), followed by Dinoroseobacter shibae DFL 12^T (95.4?% similarity). The phylogenetic distance of pufM genes between strain JLT1202r^T and R. elongatum OCh 323^T was 9.4?%, suggesting that strain JLT1202r^T was distinct from the only strain of the genus Roseibacterium. Based on the variabilities of phylogenetic and phenotypic characteristics, strain JLT1202r^T stands for a novel species of the genus Roseibacterium and the name R. beibuensis sp. nov. is proposed with JLT1202r^T as the type strain (=JCM 18015^T?=?CGMCC 1.10994^T).