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

Two bacterial strains, designated BT189^T and BT664^T, were isolated from soil sampled in the Republic of Korea. Phylogenetic analysis based on the 16S rRNA gene sequences showed that strains BT189^T and BT664^T 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 BT189^T were Hymenobacter rubidus DG7B^T (97.1 % 16S rRNA similarity) and Hymenobacter terrae DG7A^T (96.7 %). The closest related species to strain BT664^T were Hymenobacter sedentarius DG5B^T (95.3 %) and Hymenobacter terrenus MIMtkLc17^T (95.2 %). The genome sizes of strains BT189^T and BT664^T were 5 285 287 and 5 475 357 bp, respectively. The genomic DNA G+C contents of strains BT189^T and BT664^T were 63.2 and 59.3 mol%, respectively. The main fatty acids of strain BT189^T were iso-C_{15 : 0}, anteiso-C_{15 : 0} and summed feature 3 (C_{16 : 1} ω6c/C_{16 : 1} ω7c), and those of strain BT664^T were iso-C_{15 : 0}, C_{16 : 1} ω5c and summed feature 3 (C_{16 : 1} ω6c/C_{16 : 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 BT189^T (=KCTC 72341^T=NBRC 114843^T) and Hymenobacter montanus BT664^T (KACC 21967^T=NBRC 114856^T), are proposed.