Risungbinella pyongyangensis gen. nov., sp. nov., a mesophilic member of the family Thermoactinomycetaceae isolated from an agricultural soil sample

Abstract

A mesophilic strain, designed MC 210T, was isolated from an agricultural soil sample from Pyongyang, Democratic People's Republic of Korea, and its taxonomic position was investigated by using a polyphasic approach. The novel strain grew well on PYI medium, and no diffusible pigments were produced. The optimum temperature for growth was 37 °C. The aerial mycelium was well developed, but not fragmented. The strain was Gram-reaction-positive and non-motile and formed endospores on the aerial mycelium. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain MC 210T belongs to the family Thermoactinomycetaceae. Strain MC 210T showed 16S rRNA gene sequence similarities of 92.90 and 92.54  % to the type strains of Geothermomicrobium terrae and Shimazuella kribbensis, respectively. The cell wall of strain MC 210T contained meso-diaminopimelic acid, glutamic acid and alanine as the diagnostic amino acids, and whole-cell hydrolysates contained glucose, arabinose and galactose. Strain MC 210T contained anteiso-C13 : 0, iso-C14 : 0, C14 : 0, anteiso-C15 : 0, C16 : 0 and iso-C13 : 0 as the major cellular fatty acids. The main polar lipids were phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, two unknown aminophospholipids, an unknown aminolipid, three unknown phospholipids and five unknown polar lipids. The predominant menaquinone was MK-7.The G+C content of the genomic DNA was 42.1 mol%. On the basis of our phylogenetic, physiological and chemotaxonomic data, strain MC 210T is considered to represent a novel genus and species, for which we propose the name Risungbinella pyongyangensis gen. nov., sp. nov., in the family Thermoactinomycetaceae. The type strain of Risungbinella pyongyangensis is MC 210T (CCTCC AA 2013021T = NRRL B-59118T).