Pseudarthrobacter humi sp. nov., an actinobacterium isolated from soil

Abstract

A Gram- stain- positive, facultatively aerobic, rod- shaped and non- motile bacterial strain designated RMG13T was isolated from the soil near Gaetgol Eco Park and collected in Siheung- si, Republic of Korea. It was taxonomically characterized through polyphasic analysis. Phylogenetic analysis based on the 16S rRNA gene revealed that the novel isolate was most closely related to the type strains of species of the genus Pseudarthrobacter. RMG13T shared the highest similarities with Pseudarthrobacter sulfonivorans ALLT (99.2 %) and Pseudarthrobacter psychrotolerans YJ56T (99.0 %). In silico DNA-DNA hybridization values of RMG13T with P. sulfonivorans ALLT and P. psychrotolerans YJ56T were 28.1 and 41.8 %, respectively. The average nucleotide identities of RMG13T with P. sulfonivorans ALLT and P. psychrotolerans YJ56T were 84.2 and 70.3 %, respectively, whilst the average amino acid identities of RMG13T with P. sulfonivorans ALLT and P. psychrotolerans YJ56T were 90.5 and 74.6 %, respectively. Two- dimensional thin- layer chromatography showed that the major polar lipids of RMG13T were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol, and its major cellular fatty acids were anteiso- C15:0, iso-C15: 0 and anteiso- C17:0. MK- 9 (H2) was the sole menaquinone. Cells grew at 4-37 degrees C (optimum 30 degrees C) and pH 5.0-12.0 (optimum pH 8.0) in Reasoner's 2A (MB cell). The cells tolerated 0-5% NaCl (w/v) but not 6 % NaCl. The DNA G+C content of RMG13T was 65.0 %. The results of phenotypic, genotypic, chemotaxonomic and phylogenetic analyses indicated that RMG13T represents a novel member of the genus Pseudarthrobacter, and the proposed name is P. humi sp. nov. The type strain of P. humi is RMG13T (= KACC 22359T = TBRC 15115T).