PHYLOGENY OF THE GENUS CORYNEBACTERIUM DEDUCED FROM ANALYSES OF SMALL-SUBUNIT RIBOSOMAL DNA-SEQUENCES

We determined almost complete small-subunit ribosomal DNA sequences of 50 reference strains belonging to the genera Corynebacterium, Rhodoco ccus, and Gordona and compared these sequences with previously publish ed sequences, Three phylogenetic methods (the neighbor-joining, maximu m-likelihood, and maximum-parsimony methods), as well as a bootstrap a nalysis, were used to assess the robustness of each topology which we obtained, The results of comparative phylogenetic analyses confirmed t hat the genera Corynebacterium, Dietzia, Gordona, Mycobacterium, Nocar dia, Tsukamurella, and Turicella form a monophyletic taxon within the phylum containing the high-G+C-content gram-positive bacteria, The gen us Corynebacterium appeared to be a monophyletic unit whose members co uld be divided into four major clusters, The validity of the genus Tur icella is doubtful since members of this genus clearly belong to the g enus Corynebacterium, The variability of chemotaxonomic characteristic s within the genus Corynebacterium suggests that small-subunit ribosom al DNA sequence analysis is probably the most straightforward method f or confirming that a bacterium belongs to this genus.