Methylobacterium terricola sp. nov., a gamma radiation-resistant bacterium isolated from gamma ray-irradiated soil
Jiyoun Kim, Geeta Chhetri, Inhyup Kim, Byungjo Lee, Wonhee Jang, Myung Kyum Kim, Taegun Seo
Abstract
A gamma radiation-resistant and pink-pigmented bacterial strain, designated as 17Sr1-39 T , was isolated from a gamma ray-irradiated soil sample collected in the Republic of Korea. Cells were Gram-stain-negative, strictly aerobic, flagellated, asporogenous, rod-shaped and methylotrophic. Results of 16S rRNA gene sequence analysis showed that strain 17Sr1-39 T was phylogenetically related to Methylobacterium currus PR1016A T (97.3 %), Methylobacterium aquaticum DSM 16371 T (97.2 %), Methylobacterium platani PMB02 T (97.0 %), Methylobacterium frigidaeris IER25-16 T (96.6 %), Methylobacterium terrae 17Sr1-28 T (96.6 %) and Methylobacterium organophilum JCM 2833 T (93.4 %). The G+C content calculated based on the genome sequence was 70.4 mol%. The average nucleotide identity and in silico DNA–DNA hybridization values between strain 17Sr1-39 T and M. currus , M. aquaticum , M. platani , M. frigidaeris , M. terrae and M. organophilum were 77.3–89.9 and 22–38.2 %, respectively. The predominant fatty acids were summed feature 8 (C 18 : 1 ω7 c and/or C 18 : 1 ω6 c ) and summed feature 3 (C 16 : 1 ω7 c and/or C 16 : 1 ω6 c ). The predominant quinone was ubiquinone 10 and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Based on the data from phenotypic tests and genotypic differences between strain 17Sr1-39 T and its close phylogenetic relatives, strain 17Sr1-39 T represented a new species belonging to the genus Methylobacterium , for which the name Methylobacterium terricola sp. nov. (=KACC 52905 T =NBRC 112874 T ) is proposed.