Hymenobacter armeniacus sp. nov. and Hymenobacter montanus sp. nov., two radiation-resistant bacteria from soil

Two bacterial strains, designated BT189T and BT664T, were isolated from soil sampled in the Republic of Korea. Phylogenetic analysis based on the 16S rRNA gene sequences showed that strains BT189T and BT664T belonged to the genus Hymenobacter, family Hymenobacteraceae (order Cytophagales). The 16S rRNA genes of the two strains shared a sequence similarity of 93.7 %. The closely related species of strain BT189T were Hymenobacter rubidus DG7BT (97.1 % 16S rRNA similarity) and Hymenobacter terrae DG7AT (96.7 %). The closest related species to strain BT664T were Hymenobacter sedentarius DG5BT (95.3 %) and Hymenobacter terrenus MIMtkLc17T (95.2 %). The genome sizes of strains BT189T and BT664T were 5 285 287 and 5 475 357 bp, respectively. The genomic DNA G+C contents of strains BT189T and BT664T were 63.2 and 59.3 mol%, respectively. The main fatty acids of strain BT189T were iso-C15 : 0, anteiso-C15 : 0 and summed feature 3 (C16 : 1 ω6c/C16 : 1 ω7c), and those of strain BT664T were iso-C15 : 0, C16 : 1 ω5c and summed feature 3 (C16 : 1 ω6c/C16 : 1 ω7c). The main polar lipid in both strains was phosphatidylethanolamine and the predominant respiratory quinone was MK-7, supporting the affiliation of these strains with the genus Hymenobacter. Based on the results of biochemical, chemotaxonomic and phylogenetic analyses, two novel species, Hymenobacter armeniacus BT189T (=KCTC 72341T=NBRC 114843T) and Hymenobacter montanus BT664T (KACC 21967T=NBRC 114856T), are proposed.