Microlunatus elymi sp. nov., a novel actinobacterium isolated from rhizospheric soil of the wild plant Elymus tsukushiensis

Abstract

An actinobacterial strain, designated KUDC0627T, was isolated from rhizospheric soil that contained Elymus tsukushiensis on the Dokdo Islands, Republic of Korea. Cells were Gram-stain-positive, facultative anaerobic, non-motile and non-endospore-forming cocci. Results of phylogenetic analysis based on 16S rRNA gene sequences indicated that strain KUDC0627T belongs to the genus Microlunatus and is most closely related to Microlunatus soli DSM 21800T (98.5 %), Microlunatus endophyticus DSM 100019T (97.7 %) and Microlunatus ginsengisoli Gsoil 633T (96.5 %). The average nucleotide identity scores and average amino acid identity values were all below the 95.0 % cut-off point. In silico DNA–DNA hybridization, using the Genome-to-Genome Distance Calculator, estimated that there is 22.3 % DNA relatedness between KUDC0627T and M. soli DSM 21800T. The genomic DNA G+C content was 66.9 mol%. The major menaquinone was MK-9(H4) and the major diagnostic diamino acid in the cell-wall peptidoglycan was ll-diaminopimelic acid. The polar lipid profile included diphosphatidylglycerol, phosphatidylglycerol, unidentified phospholipids, unidentified glycolipids and unidentified lipids. The major cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0 and iso-C16 : 0. Based on phenotypic, chemotaxonomic, and phylogenetic data, strain KUDC0627T (=KCTC 39853T=JCM 32702T) represents a novel species, for which the name Microlunatus elymi sp. nov. is proposed.