Rhodobacter megalophilus sp nov., a phototroph from the Indian Himalayas possessing a wide temperature range for growth

Two strains of phototrophic, purple non-sulfur bacteria capable of growing at low temperatures (5 degrees C) were isolated from the Himalayas. The two strains showed positive phototaxis and grew over a relatively wide temperature range (5-40 degrees C). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JA194(T) clustered with members of the genus Rhodobacter. Strain JA194(T) showed highest 16S rRNA gene sequence similarity with Rhodobacter sphaeroides DSM 158(T) (99%). However, DNA-DNA hybridization experiments between Rba. sphaeroides DSM 158(T) and strain JA194(T) revealed a level of relatedness of only 67%. The DNA base composition of strain JA194(T) was 66.67 mol% G + C (by HPLC). Based on 16S rRNA gene sequence analysis, morphological, physiological, Fourier transform infrared fingerprinting and DNA-DNA hybridization studies, strain JA194(T) (=KCTC 5602(T) =JCM 14598(T)) is sufficiently different from other Rhodobacter species to merit its description as the type strain of a novel species, for which the name Rhodobacter megalophilus sp. nov. is proposed.