Genetic characterisation of endophytic actinobacteria isolated from the medicinal plants in Sichuan

The genetic diversity of 41 endophytic actinobacteria isolated from 13 native medicinal plants growing in diverse ecoclimatic zones in Sichuan, China, was investigated by using PCR-RFLP of the ribosomal 16S rRNA gene and the intergenic spacer (IGS) region between the 165 rRNA and 235 rRNA genes, BOX fingerprinting and full sequence analysis of the 16S rRNA gene. The results revealed 29 and 40 genotypes from 165 and 16S-23S rRNA IGS genes PCR-RFLP data, respectively, which indicated considerable genetic diversity among the isolates. Analysis of 165 rRNA gene sequences demonstrated that the strains were most closely related to representatives of the genera Streptomyces and Micromonospora among actinobacteria. Native medicinal plants are thus important resources for endophytic actinobacteria.