Knowing the origin of exotic plant pathogens introduced into a naïve territory can make the difference in managing the damages they can cause to the local economy and biodiversity. In the particular case of Xylella fastidiosa, the fact that this bacterium is present in many regions of the world in various subspecies and strains makes the task even more relevant and delicate.
The researchers compared whole-genome sequences from America and the Xylella fastidiosa sub-species multiplex strains associated with recent outbreaks in southern Europe, finding that this particular subspecies has been introduced into Europe multiple times, and once into Brazil. Most introductions into Italy, Spain, and France originated from California. The analysis unveils that X. fastidiosa subspecies multiplex itself was introduced into California, likely from the Southeastern United States.
The study also demonstrated the limits of the most widespread genetic analysis methodology, the multilocus sequence typing – MLST, supporting the utilization of whole-genome sequence data for a more accurate understanding of the relationships between strains, i.e. history of introductions, prediction of the pathogenicity. Overall, the work illustrates the risks associated with the trade of plant material at global scales and the need to develop effective policy measures to limit the likelihood of pathogen pollution into naïve regions.
Read/download via American Society for Microbiology Journals: https://doi.org/10.1128/AEM.01521-19