Deinococcus actinosclerus sp. nov., a novel bacterium isolated from soil of a rocky hillside.

Abstract

Three Gram-stain-positive, catalase- and oxidase-positive coccus- or rod-shaped bacterial strains, designated BM2T, BM4 and BM5, were isolated from soil in South Korea. They showed strong resistance to gamma radiation with a D10 value of 9 kGy but weak UVC resistance. The 16S rRNA sequences of strains BM2T, BM4 and BM5 represent a novel subline within the genus Deinococcus in the family Deinococcaceae. The 16S rRNA gene sequences of strains BM2T, BM4 and BM5 were indistinguishable and showed 98.1-87.3 % similarity with other species of the genus Deinococcus. Strain BM2T exhibited relatively high levels of DNA-DNA hybridization with BM4 (87 ± 0.8 %) and BM5 (92 ± 1.2 %). Meanwhile, it showed a low level of DNA-DNA hybridization ( < 30 %) with other closely related species of the genus Deinococcus. The strains showed the typical chemotaxonomic characteristics of the genus Deinococcus, with the presence of menaquinone 8 as the respiratory quinone; the major fatty acids were summed feature 3 (composed of C16 : 1ω7c/C16 : 1ω6c), C15 : 1ω6c and C16 : 0. The DNA G+C content of strain BM2T was 69.7 mol%. The polar lipid profile included major amounts of phosphatidylglycerol, phosphatidylcholine and an unknown aminolipid. On the basis of phenotypic and genotypic properties, and phylogenetic distinctiveness, strains BM2T, BM4 and BM5 should be classified in a novel species in the genus Deinococcus, for which the name Deinococcus actinosclerus sp. nov. is proposed. The type strain is BM2T ( = KEMB 5401-184T = JCM 30700T); reference strains are BM4 ( = JCM 30701) and BM5 ( = JCM 30702).