PHYLOGENETIC ANALYSIS REVEALS NEW RELATIONSHIPS AMONG MEMBERS OF THE GENERA MICROTETRASPORA AND MICROBISPORA

The 16S rRNA gene sequences of 7 Microbispora strains, 14 Microtetrasp ora species, 9 Streptosporangium species, and 12 Actinomadura species were determined, A phylogenetic analysis showed that Microtetraspora f usca, Microtetraspora glauca, and Microtetraspora niveoalba formed a c oherent cluster with the members of the genus Microbispora, This clust er is distantly related to two other clusters, one of which consists o f the Microtetraspora species transferred from the former Actinomadura pusilla group and one of which consists of members of the genus Strep tosporangium. Our results show that it is necessary to review the taxo nomic definitions of the genera Microtetraspora and Microbispora, whic h have been separated by a single morphological characteristic, the nu mber of spores on spore chains.