Bacterial barcoding applied to regulated plant pathogens

The BOL programs study the existing diversity of living species, but not of prokaryotes. Moreover, several bacteria pathogenic to plants are not represented by species but by pathovars which is an infra-species division that refers to a pathological specialization that is not necessary correlated with their taxonomic position. A barcode strategy is being developed in support of the European legislation on quarantine organisms on plants. Our strategy for barcode identification of the quarantine bacteria uses several gene sequences in a step wise approach and following different flows in a decision scheme. The subsequent challenges are to compose a relevant collection of the quarantine and related bacteria, to unravel their taxonomic and pathogenic identity, to generate sequences from a selected set of candidate DNA regions and select the barcode regions based on genetic variation, inclusiveness and exclusiveness for the selected scope of Q-bacteria. Barcode sequences have been defined for a group of quarantine bacteria, comprising three Clavibacter michiganensis subspecies, Ralstonia solanacearum, Xylella fastiosa and a subset of Xanthomonas pathogens.