Linking intercontinental biogeographic events to decipher how European vineyards escaped Pierce's disease

Unlike most grapevine diseases of American origin, the vector-borne bacterium Xylella
fastidiosa (Xf) responsible for Pierce's disease (PD) has not spread to continental Europe.
The reasons for this lack of invasiveness remain unclear. Here, we present phylogenetic,
epidemiological and historical evidence to explain how European vineyards escaped Xf.
Using Bayesian temporal reconstruction, we show that the export of American grapevines to
France as rootstocks to combat phylloxera (~1872-1895) preceded the spread of the Xf
grapevine lineage in the US. We also show that between 1870 and 1990, climatic conditions
in continental Europe were mostly below the threshold for PD epidemics. However, since the
1990s there has been an inadvertent expansion of risk in southern European vineyards,
which is accelerating with global warming. Our temporal approach identifies the
biogeographic conditions that have hitherto prevented PD, and how these are progressively
shifting to become a new threat to the European wine industry.