Intrageneric relationships among Micromonospora species deduced from gyrB-based phylogeny and DNA relatedness

The phylogenetic structure of genus Micromonospora within actinomycetes was examined by analysing the gyrB sequences of 15 validly described species a nd four subspecies. Ail but one of the Micromonospora strains formed a tigh t cluster, as had previously been demonstrated by a 16S rDNA-based phylogen etic analysis. however the intrageneric relationships deduced from the gyrB -based phylogeny were different from those based on their 16S rDNA sequence s. To examine which phylogeny would be more relevant for classifying genus Micromonospora, DNA-DNA hybridization experiments were performed. The gyrB- based classification agrees with the results of the DNA-DNA hybridization s tudies, indicating that this classification method is useful for analysing the phylogenetic relationships of high G+C Gram-positive bacteria at the le vel of the genomic species. Genus Micromonospora was reclassified into the following 14 species: Micromonospora echinospora, Micromonospora pallida, M icromonospora nigra, Micromonospora purpureochromogenes, Micromonospora aur antiaca, Micromonospora carbonacea, Micromonospora chalcea, Micromonospora chersina, Micromonospora coerulea, Micromonospora gallica. Micromonospora h alophytica, Micromonospora inositola, Micromonospora olivasterospora and Mi cromonospora rosaria.