In order to determine the phylogenetic structure of the actinomycete family Micromonosporuceae, the 16s ribosomal DNA sequences of 17 type species of the genera Actinoplanes, Ductylosporungium, and Pilimelia were compared with the 16s ribosomal DNA sequences of species of the genera CuteUutosporu, Cutenuloplanes, and Couchioplanes and with those of species of the genus Micromonospora and other actinomycete genera for which the sequences have been previously determined. All genera of the family, together with the genera Cutellatosporu, Cutenuloplanes, and Couchioplanes, form a phylogenetically coherent cluster that is well separated from other families of the order Actinomycetules. Except for one species of the genus Cutellatosporu, all species cluster according to their genus affiliation. The inclusion of the genera Catellatosporu, Cutenuloplanes, and Couchioplanes into the family broadens the phenotypic and chemotaxonomic heterogeneity of this taxon. An emendation of the family Micromonosporuceue is given.An emendation of the original monogeneric family Micromonosporaceae Krasilni'kov 1938 (1 1) has recently lead to an increase in the number of genera with the addition of the genera Actinoplanes, Dactylosporangum, and Pilimelia (6). The genus Catellatospora can also be considered a member of this family, as Asano and Kawamoto (1) placed this genus in the actinoplanates group of actinomycetes. The phylogenetic analysis (22) of the recently described genera Catenuloplanes (27) and Couchioplanes (22) indicated that these genera were so closely related to Actinoplanes philippinensis and Dactylosporangium aurantiacum that they could also be considered members of the family Micromonosporaceae. In contrast to many other actinomycete genera for which the phylogenetic position and taxonomic coherency have been investigated by 16s ribosomal DNA (rDNA) analysis (14, 16, 18, 25, 26), very little information is available on other genera of the family Micromonosporaceae (4, 20, 21). Until recently, sequences were available for only 3 species of the about 50 validly described species of this family (22). In a first attempt to elucidate the intrafamily structure of the family Micromonosporaceae, the intrageneric phylogenetic structure was determined for the genus Micromonospora by analyzing all type strains of the 14 presently available valid species of this genus (9). As a result, the intrageneric coherency of the genus could be confirmed. In this contribution, we extend this survey by presenting 16s rDNA sequence data on members of all genera of the family Micromonosporaceae.
MATERZALS AND METHODSStrains investigated and culture conditions. Strains investigated in this study are listed in
RESULTS AND DISCUSSIONThe almost complete 16s rDNA sequences (96% of the Escherichia coli sequence) of 17 type strains of 16 validly published species from six genera of the family Micromonosporaceae were determined and aligned with 14 recently published sequences of type strains of Micromonospora species and of Dactylosporangium thailan...