Actinokineospora soli sp. nov., a thermotolerant actinomycete isolated from soil, and emended description of the genus Actinokineospora

Abstract

A strain of thermotolerant actinomycete, designated YIM 75948T, was isolated from a soil sample in Yunnan province, China. The strain grew at 25–55 °C (optimum 37 °C). The substrate mycelium and aerial mycelium produced on Czapek’s agar were both pale yellow to white. The diagnostic diamino acid of the cell-wall peptidoglycan was meso-diaminopimelic acid, and the whole-cell sugars were mannose, ribose, glucose, galactose and arabinose. The major fatty acids were iso-C15 : 0, iso-C16 : 0 and C16 : 0 and the predominant respiratory quinone was MK-9(H4). The polar lipids consisted of phosphatidylethanolamine, phosphatidylethanolamine with hydroxy fatty acids, diphosphatidylglycerol, phosphatidylinositol and two unidentified phospholipids. The genomic DNA G+C content was 73.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YIM 75948T belonged in the genus Actinokineospora and that its closest relative among recognized species was Actinokineospora fastidiosa DSM 43855T (97.6 % sequence similarity). The mean level of DNA–DNA relatedness between the novel strain and A. fastidiosa DSM 43855T was, however, only 47.8 %. Based on the phenotypic, chemotaxonomic and phylogenetic data and the results of the DNA–DNA hybridizations, strain YIM 75948T represents a novel species of the genus Actinokineospora for which the name Actinokineospora soli sp. nov. is proposed. The type strain is YIM 75948T ( = JCM 17695T = DSM 45613T). The description of the genus Actinokineospora is emended to reflect the fact that the genomic DNA G+C contents of A. fastidiosa DSM 43855T and the type strain of Actinokineospora soli sp. nov. recorded in the present study fell above the range given in previous descriptions of this genus.