Streptosporangium terrae sp. nov., a novel actinomycete isolated from the rhizosphere of Callistemon citrinus (Curtis), India.

A novel actinomycete strain, designated VRC21(T), was isolated from the rhizosphere of Callistemon citrinus collected from Hyderabad, India. The morphological and chemotaxonomic properties of strain VRC21(T) was consistent with the characteristics of members of the genus Streptosporangium, that is, the formation of sporangia on aerial mycelium, coiled unbranched hyphae within the spore vesicle, the presence of meso-diaminopimelic acid in the cell wall, and madurose and galactose as major whole-cell sugars. Diagnostic polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol-mannosides. The predominant menaquinones were MK-9(H2) and MK-9(H4). The major cellular fatty acids were iso-C14:0, iso-C16:0, C17:0 10-methyl, C18:1w9c and C18:0 10-methyl. 16S rRNA gene sequence analyses revealed that strain VRC21(T) was a member of the genus Streptosporangium. The highest similarity values were observed with S. carneum DSM 44125(T) (98.2%) and S. fragile DSM 43847(T) (98.2%); the values of the remaining type strains were below 98%. The values of DNA-DNA relatedness between the strain VRC21(T) and the type strains of the related species were below 70%. On the basis of the polyphasic evidence, the strain VRC21(T) should be classified as novel species Streptosporangium terrae sp. nov. in the genus Streptosporangium. The type strain is VRC21(T) (=KCTC 29207(T)=MTCC 11724(T)).