Phylogenetic tree of Xanthomonas strains. Phylogenetic tree of the Xanthomonas chromosomes currently available in public databases. Based on the core genome of 2,156 CDS the divergence of these plant-pathogenic bacteria was quantified with the recently annotated Xcc B100 employed as reference to construct the tree. The Xcc genomes and Xca cluster closely together, and are linked by a common branch to the remaining Xanthomonads. Here Xca and Xcv diverge from the X. oryzae chromosomes. Among these rice pathogens Xoc forms a first side branch, while the Xoo genomes cluster together.