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

Abstract

A Gram-stain-positive, facultatively aerobic, rod-shaped and non-motile bacterial strain designated RMG13^T 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. RMG13^T shared the highest similarities with Pseudarthrobacter sulfonivorans ALL^T (99.2 %) and Pseudarthrobacter psychrotolerans YJ56^T (99.0 %). In silico DNA-DNA hybridization values of RMG13^T with P. sulfonivorans ALL^T and P. psychrotolerans YJ56^T were 28.1 and 41.8 %, respectively. The average nucleotide identities of RMG13^T with P. sulfonivorans ALL^T and P. psychrotolerans YJ56^T were 84.2 and 70.3 %, respectively, whilst the average amino acid identities of RMG13^T with P. sulfonivorans ALL^T and P. psychrotolerans YJ56^T were 90.5 and 74.6 %, respectively. Two-dimensional thin-layer chromatography showed that the major polar lipids of RMG13^T were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol, and its major cellular fatty acids were anteiso-C_{15 : 0}, iso-C_{15 : 0} and anteiso-C_{17 : 0}. MK-9 (H2) was the sole menaquinone. Cells grew at 4-37 °C (optimum 30 °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 RMG13^T was 65.0 %. The results of phenotypic, genotypic, chemotaxonomic and phylogenetic analyses indicated that RMG13^T represents a novel member of the genus Pseudarthrobacter, and the proposed name is P. humi sp. nov. The type strain of P. humi is RMG13^T (= KACC 22359^T = TBRC 15115^T).

Keywords: Pseudarthrobacter; actinobacterium; polyphasic analysis.