Data from: Virus adaptation to quantitative plant resistance: erosion or breakdown?

Adaptation of populations to new environments is frequently costly due to
trade-offs between life history traits, and consequently, parasites are
expected to be locally adapted to sympatric hosts. Also, during adaptation
to the host, an increase of parasite fitness could have direct
consequences on its aggressiveness (i.e. the quantity of damages caused to
the host by the virus). These two phenomena have been observed in the
context of pathogen adaptation to host qualitative and monogenic
resistances. However, the ability of pathogens to adapt to quantitative
polygenic plant resistances and the consequences of these potential
adaptations on other pathogen life history traits remain to be evaluated.
Using Potato virus Y and two pepper genotypes (one susceptible and one
with quantitative resistance), experimental evolutions showed that
adaptation to a quantitative resistance was possible and resulted in
resistance breakdown. This adaptation was associated to a fitness cost on
the susceptible cultivar, but had no consequence neither in terms of
aggressiveness, which could be explained by a high tolerance level, nor in
terms of aphid transmission efficiency. It results that quantitative
resistances are not necessarily durable but management strategies mixing
susceptible and resistant cultivars in space and/or in time should be
useful to preserve their efficiency.