DIVERSITY OF XYLELLA FASTIDIOSA IN FRANCE

While listed as a quarantine pest for Europe Xylella fastidiosa emerged in France and this is
evidenced through the survey of coffee plant trading from Latin America as well as the
survey of natural settings. Since the discovery of the first contaminated foci of Polygala
myrtifolia shrubs showing leaf scorch symptoms in France during 2015 summer, numerous
plants have been screened, ending in the identification of more than 300 foci. Here, we
report on the diversity of X. fastidiosa infections over the year 2015 in France in natural settings
and in imported coffee plants. Multilocus sequence typings revealed that several subspecies
and sequence types are associated to the emergence of X. fastidiosa in France. Evidences
of recombination and mixed infections in a same plant have been found. The genomes of
some strains of X. fastidiosa subsp. multiplex that were isolated in France were sequenced
and compared to their American relatives. Pathogenicity of these strains is also tested on P.
myrtifolia and other potential hosts. Altogether, these analyses suggest that X. fastidiosa has
been introduced several times in France via various plant material from different origins. This
work was done as part of INRA’s duties in WP2, task 2a and WP3, task 3a of POnTE project.