Unique resistance traits against downy mildew from the domestication center of grapevine

Climate change will increasingly challenge future viticulture due to long-enduring and extreme weather conditions, jeopardizing yield and wine quality in various ways.

Grape breeding for resistance to fungal diseases is today very dynamic throughout the world notably in France. New varieties are obtained by hybridization between susceptible varieties of the vitis vinifera species and resistant genotypes, with breeding programs generally lasting between 15 and 25 years and resulting in the registration of a few new varieties. Though these varieties can provide several benefits and can be planted by winegrowers, they are not always systematically adopted.

A consequence of climate change is the modification of grape harvest quality and physico-chemical parameters of the obtained wine: increase in alcoholic degree, decrease in pH, and modification of the extractability of macromolecules, which leads to problems of microbiological, tartaric, colour and colloidal stability. In order to respond to these problems, the winemaking processes must be anticipated and adapted with a better knowledge of macromolecule extractability in grapes and their evolution, according to the grape variety, vintage and winemaking process. The purpose of this study was to understand 1) how the harvest date can influence the extractability of macromolecules, polysaccharides and phenolic compounds, which are responsible for wine stability 2) how to adapt the winemaking process to the harvest date in order to optimise wine quality.

Botrytis cinerea has more than 1200 host plants and is one of the most important plant pathogens in viticulture. Under certain environmental conditions, it can lead to the development of a noble rot, which results in a specific metabolic profile, altering physical texture and chemical composition. The other microbes involved in this process and their functional genes are poorly characterised. We have generated metatranscriptomic [1,2] and DNA metabarcoding data from three months of the Furmint grape variety, representing the four phases of noble rot, from healthy berries to completely dried berries.

Les enzymes d’oxydation (polyphénoloxydase, peroxydase) des raisins sont d’origine génétique dépendantes des facteurs climatiques et agrotechniques (Sapis et al, 1983). Dans le processus technologique de l’obtention du moût de raisins, ces enzymes catalysent l’oxydation de certains composés phénoliques naturellement présents dans le raisin, produisant ainsi des modifications indésirables de la couleur et de l’arôme du vin.