Streptomyces endophyticus sp. nov., an endophytic actinomycete isolated from Artemisia annua L.

Abstract

Three filamentous actinomycetes, strains YIM 65594T, YIM 65638 and YIM 65642, were isolated from the surface-sterilized roots of Artemisia annua L. collected from Yunnan province, south-west China. These strains were found to have morphological and chemotaxonomic characteristics typical of the genus Streptomyces . The organisms formed an extensively branched substrate mycelium, with abundant aerial hyphae that differentiated into spores. The cell wall of the isolates contained ll-diaminopimelic acid and the menaquinones were MK-9(H8) and MK-9(H6). The major fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. Phylogenetic analysis of the 16S rRNA gene sequences of these strains revealed that the strains clustered together and were most closely related to Streptomyces kunmingensis NBRC 14463T, with 98.5–98.6 % 16S rRNA gene sequence similarity. The results of DNA–DNA hybridization and physiological tests allowed the genotypic and phenotypic differentiation of strains YIM 65594T, YIM 65638 and YIM 65642 from related species. However, the high level of DNA–DNA relatedness between them showed that these three strains belong to the same species. Strain YIM 65594T ( = DSM 41984T = CCTCC AA 209036T) was selected as the type strain to represent this novel species, for which the name Streptomyces endophyticus sp. nov. is proposed.