Hymenobacter guriensis sp. nov., and Hymenobacter duratus sp. nov., Radiation-Resistant Species Isolated from Soil in South Korea

Two novel Gram-stain-negative, non-motile, aerobic, rod-shaped, circular, convex, red-colored and UV-tolerant strains BT594(T) and BT646(T) were isolated from soil collected in Guri city (37 degrees 36' 0 '' N, 127 degrees 9' 0 '' E) and Gwangju city (37 degrees 22' 0 '' N, 127 degrees 17' 0 '' E), respectively, South Korea. 16S rDNA sequence analysis indicated that strains BT594(T) and BT646(T) belong to a distinct lineage within the genus Hymenobacter (family Hymenobacteraceae, order Cytophagales, class Cytophagia, phylum Bacteroidetes, kingdom Bacteria). The 16S rDNA gene sequence similarity between the two strains BT594(T) and BT646(T) was 96.2%. The strain BT594(T) was closely related to Hymenobacter psychrotolerans Tibet-IIU11(T) (97.0% 16S rDNA gene similarity) and Hymenobacter tibetensis XTM003(T) (96.3%). The strain BT646(T) was closely related to Hymenobacter psychrotolerans Tibet-IIU11(T) (98.6%), Hymenobacter kanuolensis T-3(T) (96.8%) and Hymenobacter perfusus LMG 26000(T) (96.7%). The two strains were found to have the same quinone system, with MK-7 as the major respiratory quinone. The major polar lipids of strains BT594(T) and BT646(T) were phosphatidylethanolamine (PE) and aminophospholipids (APL). The major cellular fatty acids of strain BT594(T) were anteiso-C-15:0 (17.9%), iso-C-15:0 (16.1%) and summed feature 3 (C-16:1 omega 6c/C-16:1 omega 7c) (10.0%). The major cellular fatty acids of strain BT646(T) were summed feature 3 (C-16:1 omega 6c/C-16:1 omega 7c) (18.3%), C-16:0 (17.2%) and summed feature 4 (iso-C17:1 I/anteiso-C-17:1 B) (14.5%). Based on the polyphasic analysis, strains BT594(T) and BT646(T) can be suggested as two novel bacterial species within the genus Hymenobacter and the proposed names are Hymenobacter guriensis and Hymenobacter duratus, respectively. The type strain of Hymenobacter guriensis is BT594(T) (=KCTC 21863(T) = NBRC 114853(T)) and the type strain of Hymenobacter duratus is BT646(T) (=KCTC 21915(T) = NBRC 114854(T)).

Automated summary

Two novel strains BT594(T) and BT646(T) of the genus Hymenobacter, isolated from soil in South Korea, show a high similarity in their 16S rDNA sequences and can be suggested as two new species, named Hymenobacter guriensis and Hymenobacter duratus, respectively, based on polyphasic analysis.