An endophytic actinobacterium, strain WES2T, was isolated from the stem of a jasmine rice plant collected from a paddy field in Thung Gura Rong Hai, Roi Et province, Thailand. As a result of a polyphasic study, this strain was identified as representing a novel member of the genus Streptomyces. This strain was a Gram-stain-positive, aerobic actinobacterium with well-developed substrate mycelia and forming chains of looped spores. The closest phylogenetic relations, which shared the highest 16S rRNA gene sequence similarity, were Streptomyces nogalater JCM 4799T and Streptomyces lavenduligriseus NRRL-ISP 5487T at 99.1 and 99.0 %, respectively. Chemotaxonomic data, including major fatty acids, cell wall components and major menaquinones, confirmed the affiliation of WES2T to the genus Streptomyces. The data from the phylogenetic analysis, including physiological and biochemical studies and DNA-DNA hybridization, revealed the genotypic and phenotypic differentiation of WES2T from the most closely related species with validly published names. The name proposed for the novel species is Streptomycesroietensis sp. nov. The type strain is WES2T (=DSM 101729=NRRL B-65344).
Keywords: Streptomyces; endophyte; jasmine rice; sp. nov.