Exogenous dsRNA applications to identify novel candidate susceptibility genes to downy mildew

There is an urgent need in viticulture to adopt alternative herbicide-free soil management strategies to mitigate climate change, increase biodiversity, reduce plant protection products and improve soil quality while minimizing detrimental effects on grapevine’s stress tolerance and fruit quality. To propose sustainable solutions, adapted to different pedoclimatic conditions in Switzerland, we developed a multidisciplinary 4-year project, started in 2020. Objectives of the project are to a) evaluate the impact of green covers (spontaneous flora, winter cover crop and permanent ground cover) on environmental and agronomic parameters and b) develop subsequently innovative strategies for different viticultural contexts of Switzerland. The project is divided into 3 phases: 1) diagnosis, 2) on-farm and 3) on-station experiments. Phase 1) consisted in an assessment of 30 commercial vineyards all over Switzerland, where growers already use different herbicide-free soil management strategies. The most promising practices identified in this exploratory phase will be replicated in commercial vineyards across Switzerland (“on-farm”) as well as in a classical randomized block design in an experimental plot (“on-station”). For phase 1), measurements consisted in evaluation of soil status (compaction, structure, roots development), soil microbial diversity (metagenomics), plant diversity and biomass, vine physiology (water stress, vigor, leaf nitrogen) and berry quality (acidity, sugar, available nitrogen). Interestingly, the permanent ground cover resulted in a higher Shannon index thus a higher biodiversity as compared to the other itineraries. The winter cover crop increased vine nitrogen and vigor while deteriorating soil quality, leaving the soil more exposed and compacted likely due to more frequent tillage. The spontaneous flora led to higher berry sugar accumulation, less nitrogen and higher malic acid concentration putatively due to a higher water retention of the flora in a particularly wet vintage. Phases 2) and 3) are required to confirm those tendencies, over the 3 next vintages and different climatic conditions.

The interaction between mannoproteins and wine phenolic compounds is a subject of great interest as some studies show the possible impact in color stability and an improvement in the sensory characteristics namely the reduction of red wine astringency.

Untargeted metabolomics has proven to be an effective method to study the impact of the terroir on metabolic profile of wines. In this context, the aim of this study was to evaluate the effects of different soil types on the chemical composition of Mediterranean red wines, through 1H-NMR metabolomics combined with chemometrics.Grapes from Nero d’Avola L. red cultivar cultivated on four different soil types were separately vinified to obtain four different red wines.One milliliter of raw wine was analyzed by means of a Bruker Avance II 400 spectrometer operating at 400.15 MHz

The metabolomics era started about 22 years ago, and wine was one of the first foodstuff subjects of analysis and investigation by this technique.

Dehydrodicatechins have recently received attention as oxidation markers especially in grapes and wine. Their analysis mainly uses LC-MS/MS which is able to differentiate them from their natural isomers (dimeric procyanidins), based on specific fragments