Dietzia schimae sp. nov. and Dietzia cercidiphylli sp. nov., from surface-sterilized plant tissues.

Two actinobacterial strains, YIM 65001(T) and YIM 65002(T), were isolated from surface-sterilized plant tissues collected from Yunnan Province, south-west China, and their taxonomic positions were determined by using a polyphasic approach. The DNA G+C contents of strains YIM 65001(T) and YIM 65002(T) were 71.9 and 72.6 mol%, respectively. The two strains had chemotaxonomic markers that were consistent with their classification in the genus Dietzia. Phylogenetic analysis based on almost-complete 16S rRNA gene sequences indicated that strain YIM 65001(T) was related most closely to Dietzia maris DSM 43672(T) and that strain YIM 65002(T) was related most closely to Dietzia natronolimnaea CBS 107.95(T). Levels of 16S rRNA gene sequence similarity between strains YIM 65001(T) and YIM 65002(T) and the type strains of other recognized members of the genus Dietzia were 95.8-99.8 %. DNA-DNA hybridization experiments confirmed the separate genomic status of strains YIM 65001(T) and YIM 65002(T). Strains YIM 65001(T) and YIM 65002(T) showed significant phenotypic differences between each other and their closest recognized neighbours. On the basis of their phenotypic and phylogenetic distinctiveness, the two novel isolates were identified as representing two novel species of the genus Dietzia, for which the names Dietzia schimae sp. nov. (type strain YIM 65001(T)=CCTCC AA 207015(T)=DSM 45139(T)) and Dietzia cercidiphylli sp. nov. (type strain YIM 65002(T)=CCTCC AA 207016(T)=DSM 45140(T)) are proposed.