Deinococcus rubrus sp. nov., a Bacterium Isolated from Antarctic Coastal Sea Water.

Two Gram-staining-negative, red-pinkish, coccus-shaped, non-motile, and aerobic bacterial strains, designated Ant21(T) and Ant22, were isolated from the Antarctic coastal sea water. Strains Ant21(T) and Ant22 showed UVC and gamma radiation resistance. Phylogenetic analyses based on 16S rRNA gene sequences determined that these strains belong to the genus Deinococcus. Through the analyses of the 16S rRNA gene sequences, strains Ant21(T) and Ant22 were found to have 97.7% and 97.8% similarity to Deinococcus marmoris DSM 12784(T) and 97.0% and 97.2% similarity to Deinococcus saxicola AA-1444(T), respectively. The sequence similarity with the type strains of other Deinococcus species was less than 96.9% for both strains. Strains Ant21(T) and Ant22 shared relatively high 16S rRNA gene sequence similarity (99.3%) and had a closely related DNA reassociation value of 84 ± 0.5%. Meanwhile, they showed a low level of DNA-DNA hybridization (<30%) with other closely related species of the genus Deinococcus. The two strains also showed typical chemotaxonomic features for the genus Deinococcus, in terms of the major polar lipid (phosphoglycolipid) and the major fatty acids (C16:0, C16:1ω6c/ω7c, iso-C17:0 , and iso-C15:0). They grew at temperatures between 4°C and 30°C and at pH values of 6.0-8.0. Based on the physiological characteristics, the 16S rRNA gene sequence analysis results, and the low DNA-DNA reassociation level with Deionococcus marmoris, strains Ant21(T) (= KEMB 9004-167(T) =JCM 31436(T)) and Ant22 (KEMB 9004-168 =JCM 31437) represent novel species belonging to the genus Deinococcus, for which the name Deinococcus rubrus is proposed.