In the framework of the project XF-ACTORS the genetic characterization of the strains cultured from different hosts identified in the outbreak discovered last December in Tuscany, has been completed revealing that a single and novel genotype – denoted “Sequence Type ST87” of the subspecies multiplex was associated with the infections so far detected in this outbreak.
Beside the widely used MLST approach, a preliminary assessment of the subspecies was successfully accomplished using a rapid test based on a single real time PCR test followed by the so called High Resolution Melting analysis.
The finding in this outbreak of a novel genotype of the subspecies multiplex confirms that several strains of this subspecies are present in different and distinct EU outbreaks, suggesting that so far the emergence of the pathogen in Europe is mostly related to multiple introductions occurred in the past rather than to movement and exchange of infected materials within Europe. However, additional information on the relatedness of these strains and those previously described in Europe and America are expected to be gathered from the ongoing whole genome sequencing of the cultured isolates.
The work is co-authored by the researchers of the CNR-IPSP and University of Bari, and the phytosanitary Inspector of the Regional Plant Health Agency (SFR Toscana).