Tree of the concatenated nucleotide sequences of seven housekeeping genes ( gyrB , atpD , dnaK , efp , groEL , glnA and recA ) using the maximum likelihood method and GTR as substitution model. The tree was constructed with Burkholderia pseudomallei strain NCTC 10247 as outgroup. The total length of the concatenated nucleotide sequences was between 10417-10686 bp. Bootstrap percentages retrieved in 500 replications are shown at the nodes. The scale bar (0.2) indicates the number of nucleotide substitutions per site. The long branch separating the Xanthomonadaceae from the two other distant taxa (B. pseudomallei strain NCTC 10247 and Ralstonia solanacearum strain GMI1000) has been shortened.