Litoreibacter roseus sp. nov., a novel bacteriochlorophyll a-containing bacterium

A strictly aerobic, bacteriochlorophyll (BChl) a-containing alphaproteobacterium, designated strain K6^T, was isolated from seawater around an aquaculture site in the Uwa Sea in Japan. The novel strain grew optimally at 30 °C at pH 7.0-7.5 and in the presence of 2.0 % (w/v) NaCl. The nonmotile and coccoid or rod-shaped cells formed pink-pigmented colonies on agar plates containing organic compounds. Cells showed an in vivo absorption maximum at 870 nm in the near-infrared region, indicating the presence of BChl a in the light-harvesting 1 complex. The new bacterial strain was Gram-stain-negative and oxidase- and catalase-positive. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain K6^T was closely related to species in the genus Litoreibacter. The closest phylogenetic relatives of strain K6^T were Litoreibacter ponti GJSW-31^T (98.56 % sequence similarity), Litoreibacter janthinus KMM 3842^T (97.63 %) and Litoreibacter albidus KMM 3851^T (96.88 %). The G+C content of the genomic DNA was 58.26 mol%. The average nucleotide identity value of strain K6^T with the type strain of L. ponti was 77.16 % (SD 4.79 %). The digital DNA-DNA hybridization value of strain K6^T with the type strain of L. ponti was 19.40 %. The respiratory quinone was ubiquinone-10. The major cellular fatty acids were C_18 : 1 ω7c, C_16 : 0 and 11-methyl C_18 : 1 ω7c. The dominant polar lipids were phosphatidylcholine and phosphatidylglycerol. On the basis of the genetic and phenotypic data obtained in the present study, we propose a new species in the genus Litoreibacter: Litoreibacter roseus sp. nov., whose type strain is K6^T (=DSM 110109^T=NBRC 114114^T). Strain K6^T represents the first confirmed species that produces BChl a within the genus Litoreibacter.