Dactylosporangium siamense sp. nov., isolated from soil

Abstract

A novel actinomycete strain, designed MW4-36T, was isolated from tropical forest soil in Nakhon Sawan Province, Thailand. Morphological and chemotaxonomic characteristics of this strain clearly demonstrated that it belongs to the genus Dactylosporangium . The strain formed finger-shaped sporangia on short sporangiophores that emerged directly from substrate hyphae. The cell-wall peptidoglycan contained glutamic acid, glycine, alanine and meso-diaminopimelic acid including 3-hydroxy-meso-diaminopimelic acid; arabinose, glucose, rhamnose, ribose and xylose were found as whole-cell sugars. The diagnostic phospholipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol; no phosphatidylcholine was found. The predominant menaquinones were MK-9(H8) and MK-9(H6). Mycolic acids were not detected. The predominant cellular fatty acids were iso-C15 : 0, iso-C16 : 0, anteiso-C15 : 0 and anteiso-C17 : 0. The G+C content of the genomic DNA was 72.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences also indicated that the strain should be classified in the genus Dactylosporangium and showed that the closest relative was Dactylosporangium maewongense JCM 15933T (99.4 % similarity). These taxonomic data revealed that strain MW4-36T could be readily distinguished from its phylogenetically closest relative. On the basis of these phenotypic and genotypic data, strain MW4-36T is considered to represent a novel species, for which the name Dactylosporangium siamense sp. nov. is proposed. The type strain is MW4-36T ( = BCC 34901T = NBRC 106093T).