Dactylosporangium darangshiense sp. nov., isolated from rock soil

Abstract

A novel actinomycete was isolated from soil of a rock surface collected from the peak of Darangshi Oreum (Small Mountain) in Jeju, Republic of Korea. Phylogenetic analyses based on 16S rRNA gene sequences demonstrated that strain DLS-44(T) belonged to the genus Dactylosporangium, with the type strains of Dactylosporangium roseum (99.1 % sequence similarity) and Dactylosporangium fulvum (99.0 %) as the nearest phylogenetic relatives. Substrate mycelium was abundant, irregularly branched, twisted and vivid orange-yellow in colour. Aerial mycelium was not produced on most media tested. Finger-shaped sporangia and globose bodies were formed directly from the vegetative mycelium. The combination of morphological and chemotaxonomic characteristics supported assignment of the actinomycete to the genus Dactylosporangium. Strain DLS-44(T) could be distinguished clearly from all type strains of the genus based on its physiological properties (utilization of methyl alpha-d-mannoside and glycerol, nitrate reduction and growth at 20 degrees C and pH 9.1) and some chemotaxonomic characteristics (absence of unsaturated fatty acids). DNA-DNA relatedness values between strain DLS-44(T) and its closest phylogenetic relatives were 12.2-14.8 % with D. roseum DSM 43916(T) and 2.5-3.6 % with D. fulvum IMSNU 22055(T). On the basis of phenotypic, phylogenetic and DNA-DNA hybridization data, strain DLS-44(T) represents a novel species of the genus Dactylosporangium, for which the name Dactylosporangium darangshiense sp. nov. is proposed. The type strain is strain DLS-44(T) (=KCTC 19560(T) =DSM 45260(T)).