Abstract:In order to develop new biologically active substances in medicinal plants, an isolation and culture method was employed to investigate the taxonomic diversity and anti-microbial activities of endophytic actinomycetes isolated from Stellera chamaejasme sampled in Aba, Sichuan. It was found that the number of isolates was affected by many factors, especially organic matter content which was significantly positively correlated with the isolate number (P<0.05, r=0.86). Fifty two isolates were obtained on Gauze No.1 growth medium, accounting for 30.4% of total isolations. The numbers of isolates decreased in the following order: root, stem, leaf and flower. Analysis using 16S rDNA-RFLP divided these isolated strains into 11 clusters and further phylogenic analysis classified representative strains as genera Streptomyces, Nocardia, Kitasatospora and Kribbella, respectively, with Streptomyces being predominant. PKS (4) and NRPS (2) genes were detected in the study and most of representative strains had antibiotic activity towards the pathogenic fungal strains, with SCAUEⅢD11-1 being most potent. It is concluded that behavior of isolates of endophytic actinomycetes from S. chamaejasme is affected by many factors with resulting diversity of expression. Functional genes and antibiotic activity indicated endophytic actinomycetes from S. chamaejasme sampled in Aba had potential medicinal value.