Roseobacter fucihabitans sp. nov., isolated from the brown alga Fucus spiralis

A Gram-negative, aerobic, pink-pigmented, and bacteriochlorophyll a-containing bacterial strain, designated B14^T, was isolated from the macroalga Fucus spiralis sampled from the southern North Sea, Germany. Based on 16S rRNA gene sequences, species of the genera Roseobacter and Sulfitobacter were most closely related to strain B14^T with sequence identities ranging from 98.15 % (Roseobacter denitrificans Och 114^T) to 99.11 % (Roseobacter litoralis Och 149^T), whereas Sulfitobacter mediterraneus CH-B427^T exhibited 98.52 % sequence identity. Digital DNA-DNA hybridization and average nucleotide identity values between the genome of the novel strain and that of closely related Roseobacter and Sulfitobacter type strains were <20 % and <77 %, respectively. The novel strain contained ubiquinone-10 as the only respiratory quinone and C_18 : 1 ω7c, C_16 : 0, C_18 : 0, C_12 : 1 ω7c, C_18 : 2 ω7,13c, and C_10 : 0 3-OH as the major cellular fatty acids. The predominant polar lipids of strain B14^T were phosphatidylcholine, phosphatidylethanolamine, and phosphatidylglycerol. The genome of strain B14^T comprises a chromosome with a size of 4.5 Mbp, one chromid, and four plasmids. The genome contains the complete gene cluster for aerobic anoxygenic photosynthesis required for a photoheterotrophic lifestyle. The results of this study indicate that strain B14^T (=DSM 116946^T=LMG 33352^T) represents a novel species of the genus Roseobacter for which the name Roseobacter fucihabitans sp. nov. is proposed.