Dyadobacter psychrotolerans sp. nov. and Dyadobacter frigoris sp. nov., two novel psychrotolerant members of the family Cytophagaceae isolated from Arctic soil

Four strains of bacteria designated as AR-3-6 T , AT-3-1, AR-3-8 T and AR-3-15 were isolated from Arctic soil. Cells were aerobic, Gram-staining-negative, non-motile, non-spore-forming, rod-shaped and yellow-pigmented. Flexirubin-type pigments were present in all strains. All strains tolerated 2 % of NaCl and were psychrotolerant. A phylogenetic analysis based on its 16S rRNA gene sequence revealed that these strains formed a lineage within the family Cytophagaceae hat were distinct from various members of the genus Dyadobacter . The closest member of strain AR-3-6 T was D. koreensis DSM 19938 T (97.2 % sequence similarity) and AR-3-8 T was D. hamtensis HHS 11 T (97.9 %). The predominant respiratory quinone was menaqinone-7. The major polar lipid was phosphatidylethanolamine. The major cellular fatty acids were summed feature 3 (C 16 : 1 ω7c and/or C 16 : 1 ω6 c ), iso-C 15 : 0 , C 16 : 1 ω5 c and iso-C 17 : 0 3-OH. The DNA G+C content of strains ranges from 40.1 to 42.1 mol%. On the basis of phenotypic, genotypic, chemotaxonomic and phylogenetic analysis, both strains AR-3-6 T and AR-3-8 T represent a novel member in the genus Dyadobacter , for which the name Dyadobacter psychrotolerans sp. nov. and Dyadobacter frigoris sp. nov. are proposed, respectively. The type strain of Dyadobacter psychrotolerans is AR-3-6 T (=KEMB 9005-743 T =KACC 21172 T =NBRC 113790 T ) and type strain of Dyadobacter frigoris is AR-3-8 T (=KEMB 9005-744 T = KACC 21173 T =NBRC 113791 T ).