Two reddish-coloured bacterial strains (HMF7604T and HMF7620T) were isolated from bark of birch tree (Betula platyphylla) together with two strains (designed as HMF7603 and HMF7618). Cells were observed to be Gram-stain-negative, oval- to short rod-shaped and non-motile. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the four isolates belonged to the genus Deinococcus, family Deinococcaceae. They had the highest similarities (95.4-95.6 %) to Deinococcus multiflagellatus ID1504T, with which they formed a clade in phylogenetic trees. Menaquinone-8 was the only respiratory quinone. The predominant fatty acids were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C15 : 1 ω6c, C17 : 0 and C16 : 0. Strain HMF7604T contained two unidentified phosphoglycolipids, nine unidentified glycolipids, one unidentified aminolipid, three unidentified phospholipids and three unidentified polar lipids, while strain HMF7620T contained one unidentified phosphoglycolipid, four unidentified glycolipids, one unidentified aminophospholipid, one unidentified phospholipid and one unidentified polar lipid. The DNA G+C contents of strains HMF7604T and HMF7620T were 65.6 and 65.7 mol%, respectively. The average nucleotide identity and digital DNA-DNA hybridization values between the two isolates and their close relative D. multiflagellatus were 81.1-95.3 and 24.5-61.6 %, respectively. Based on the results of phenotypic and phylogenetic characterizations, the four isolates are considered to represent two novel species of the genus Deinococcus, for which the names Deinococcus betulae sp. nov. and Deinococcus arboris sp. nov. are proposed. The type strains are HMF7604T (=KCTC 43354T=NBRC 115489T) and HMF7620T (=KCTC 43051T=NBRC 113959T).
Keywords: 16S rRNA gene; bark; betula platyphylla; birch tree; deinococcus.