Reclassification of Burkholderia insecticola as Caballeronia insecticola comb. nov. and reliability of conserved signature indels as molecular synapomorphies

In the last 4 years, most of the species previously classified as members of the genus Burkholderia have been transferred to the novel genera Paraburkholderia, Caballeronia, Robbsia, Mycetohabitans and Trinickia. However, there have been objections to splitting the genus Burkholderia sensu lato, and based on this taxonomic opinion, strain RPE64(T), which has the 16S rRNA gene sequence identical to that of Caballeronia peredens LMG 29314(T), has recently been proposed as the type strain of Burkholderia insecticola sp. nov. The arguments against the split were analysed in this study and found to be not convincing enough to revise the taxonomic positions of members of the novel genera. Therefore, based on the results of phylogenetic analyses, including comparisons of 16S rRNA gene sequences and those of concatenated proteins, as well as on the fact that strain RPE64(T) had all molecular signatures included as Caballeronia-specific markers in the genus description, we propose to reclassify B. insecticola as Caballeronia insecticola comb. nov. The results of this study also showed that 'Burkholderia novacaledonica' and 'Burkholderia ultramafica' should be transferred to the genera Caballeronia and Paraburkholderia, respectively.