Phylogeny of the Mycoplasma mycoides cluster based on analysis of five conserved protein-coding sequences and possible implications for the taxonomy of the group

Abstract

A phylogenetic tree of theMycoplasma mycoidescluster was inferred from a set of concatenated sequences from five housekeeping genes (fusA,glpQ,gyrB,lepAandrpoB). The relevance of this phylogeny was reinforced by detailed analysis of the congruence of the phylogenies derived from each of the five individual gene sequences. Two subclusters were distinguished. TheM. mycoidessubcluster comprisedM. mycoidessubsp.mycoidesbiotypes Small Colony (SC) and Large Colony (LC) andM. mycoidessubsp.capri. The latter two groups could not be clearly separated, which supports previous proposals that they be united into a single taxonomic entity. TheMycoplasma capricolumsubcluster includedM. capricolumsubsp.capricolum,M. capricolumsubsp.capripneumoniaeandMycoplasmasp. bovine group 7 of Leach, a group of strains that remains unassigned. This group constituted a distinct branch within this cluster, supporting its classification as a subspecies ofM. capricolum.Mycoplasma cottewiiandMycoplasma yeatsiiclustered in a group that was distinct fromMycoplasma putrefaciensand they were all clearly separated from theM. mycoidescluster. In conclusion, this approach has allowed us to assign phylogenetic positions to all members of theM. mycoidescluster and related species and has proved the need to adjust the existing taxonomy. Furthermore, this method may be used as a reference technique to assign an unequivocal position to any particular strain related to this cluster and may lead to the development of new techniques for rapid species identification.