Exploring the impact of NPR3 gene silencing on the interaction between grapevine and mycorrhizal fungi through genome editing

Condensed tannins (also called proanthocyanidins) are a widely distributed throughout in plants kingdom and are one of the most important classes of secondary metabolites, in addition, they are part of the human diet. In wine, they are extracted during the winemaking process from grape skins and seeds. These compounds play an important role in red wine organoleptic characteristics such as color, bitterness and astringency. Condensed tannins in red wine are oligomers and polymers of flavan-3-ols unit such as catechin, epicatechin, epigallocatechin and epicatechin-3-O-gallate. The monomeric units can be linked among them with direct interflavanoid linkage or mediated by aldehydes.

The demand for dealcoholized wine has been progressively increasing in recent years. Moreover, the attention for such products is probably increasing even more. Due to that increasing demand and market awareness the legal authorities are about changing rules for that products. Also, at OIV level, these products are being intensively discussed for certain time. The production of dealcoholized wine bases on wine as initial product. This wine is then reduced by physical methods to an alcohol content of less than 0.5% vol., or in other words, to less than 4g/l of alcohol. There are various technologies are possible for producing dealcoholized wine (Schmitt and Christmann 2019).

Mannoproteins are macromolecules found on the surface of yeast cells, composed of hyperbranched polysaccharide negatively charged chains by mannosyl-phosphate groups, fixed to a protein core. during the alcoholic fermentation and aging on lees, these mannoproteins are released from the yeast cell wall and become the main yeast-sourced polysaccharide in wine. due to their techno-functional properties, commercial preparations of mannoproteins can be used as additives to better assure tartaric and protein stability.

The technique of crossing, whether free or controlled, has always been a source of variability allowing the selection of new varieties with improved fitness.

Wine grapes have the ability to accumulate high amounts of hexoses (glucose and fructose), which is considered one of the main processes occurring during the ripening stage. Sugar accumulation dynamics respond to genetic, environmental and vineyard management factors, with a changing climate leading to advanced and faster sugar accumulation worldwide. Research on mitigation techniques to this phenomenon is ongoing, with the largest focus being vineyard techniques to delay sugar accumulation. Breeding represents another powerful tool to address the issue of high sugar concentration at harvest, since historical trends of selecting best sugar-accumulators may be inverted to breed varieties that accumulate diminished concentrations of hexoses while maintaining optimal acidity, color, mouthfeel and aroma compounds.