Phylogeny of the family Pasteurellaceae based on rpoB sequences

Abstract

Sequences of the gene encoding theβ-subunit of the RNA polymerase (rpoB) were used to delineate the phylogeny of the familyPasteurellaceae. A total of 72 strains, including the type strains of the major described species as well as selected field isolates, were included in the study. Selection of universalrpoB-derived primers for the family allowed straightforward amplification and sequencing of a 560 bp fragment of therpoBgene. In parallel, 16S rDNA was sequenced from all strains. The phylogenetic tree obtained with therpoBsequences reflected the major branches of the tree obtained with the 16S rDNA, especially at the genus level. Only a few discrepancies between the trees were observed. In certain cases therpoBphylogeny was in better agreement with DNA–DNA hybridization studies than the phylogeny derived from 16S rDNA. TherpoBgene is strongly conserved within the various species of the family ofPasteurellaceae. Hence,rpoBgene sequence analysis in conjunction with 16S rDNA sequencing is a valuable tool for phylogenetic studies of thePasteurellaceaeand may also prove useful for reorganizing the current taxonomy of this bacterial family.