Methylobacterium radiodurans sp. nov., a novel radiation-resistant Methylobacterium.

A Gram-negative, aerobic, flagellated, rod-shaped, and pink-pigmented bacterium, strain 17Sr1-43, was isolated from a soil sample collected in Nowongu, Seoul, Korea. The isolate could grow at 18-37 °C (optimum, 28-30 °C), pH 6.0-8.0 (optimum, pH 7.0) and in the presence of 0-1.0% (w/v) NaCl (optimum, 0%) with aeration. The major cellular fatty acids were summed feature 8 (C ω7c and/or C ω6c) and summed feature 2 (iso-C I and/or C 3-OH). The predominant respiratory quinone was Q-10 and the major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phospholipid, and diphosphatidylglycerol. The G + C content of genomic DNA was 69.1 mol%. Strain 17Sr1-43 was closely related to Methylobacterium gregans KACC 14808 (98.4% 16S rRNA gene sequence similarity), Methylobacterium hispanicum KACC 11432 (97.9%), and Methylobacterium phyllosphaerae CBMB27 (96.1%). The complete genome of strain 17Sr1-43 contains essential genes related to DNA repair processes including bacterial RecBCD dependent pathway and UmuCD system. Based on the phenotypic, genotypic, and chemotaxonomic characteristics, strain 17Sr1-43 represents a novel species in the genus Methylobacterium, for which the name Methylobacterium radiodurans sp. nov. is proposed. The type strain is strain 17Sr1-43 (= KCTC 52906 = NBRC 112875).