Simulating the impact of climate change on disease-resistant grapevine varieties

Abstract: Grapevine cultivation is subjected to a wide variety of abiotic and biotic stresses.
Several disease-resistance grapevine varieties have been released in the last decades and their
cultivated surfaces are now expanding to reduce the environmental impact of viticulture.
However, the behaviour of these varieties under climate change-triggered abiotic stresses
remains poorly characterized. In our work, six grapevine varieties, including disease-resistant
genotypes, were used to set up multistress experiments, consisting in a sequential combination of heat stress, generated with an innovative thermic stress platform, and infections with Plasmopara viticola, the causal agent of grape downy mildew. The heat stress induced morphophysiological changes as a generalized reduced stomatal conductance and genotype-dependent leaf burn and reduced plant growth. The pathotests with downy mildew yielded contrasting results and showed after the heatwaves a reduced susceptibility or resistance to P. viticola according to the tested variety. In conclusion, our preliminary experience showed that heatwaves can affect both the plant physiology and response to downy mildew in PIWI varieties.