Use of antisense RNA technology to modulate gene expression in Œnococcus oeni

The advance in maturation of wine grapes is an important climate change risk related effect that could affect warm regions like Portuguese Douro Wine Region. Indeed, the climate analysis over the past years registered a decrease in the precipitation, significant higher average temperatures, and a more frequent occurrence of extreme weather events, including heat waves. In these conditions the length from anthesis until maturation is shortened and the uncoupling of technical and phenolic maturity results in berries with higher sugar concentration (and lower acidity), but lower anthocyanins, tannins, and total phenolic concentration, which produce unbalanced wines.
In this work, an innovative strategy of crop forcing, based on forcing vine regrowth after a second pruning of green shoots, was tested, aimed at delaying ripening until the temperature becomes lower and, therefore, preventing acidity loss and increasing anthocyanin-to-sugar ratio. The experiments were conducted in 2019 and 2020 in a commercial vineyard of ‘Touriga Nacional’ located in the Douro Region. Crop forcing was conducted 15 (CF1) to 30 (CF2) days after fruit set. Vines pruned with conventional methods were used as control (CF0). Results confirmed that fruit ripening was shifted from the hot season (August/September), until a cooler period (October through early-November). At harvest, grapevine berries from CF1 and CF2 presented lower pH and higher acidity, than control, with no significant differences in colour intensity and phenolic levels composition. Sugar content was lower in CF2-treated vines in both seasons. However, in CF-treated vines the number and size of clusters were significantly lower (up to 88% reduction) than in control plants. A metabolomics analysis of mature berries from CF-treated vines and control is underway. Crop forcing was indeed effective in producing a more balance berry composition but severely reduced grapevine yield,

The production of fine wines in the Sub-middle of the São Francisco River Valley, Northeast of Brazil, is relatively recent, about twenty-five years ago. This region presents different characteristics

Among the main plant secondary metabolites, glycosides have a key-role in wine chemistry. Glycosides are non-volatile complex composed of a non-sugar component (aglycone) bound to one or more carbohydrates.

Plus de la moitié du vignoble suisse (14’000 ha) est situé sur des coteaux en forte pente (> 30%). Dans certains vignobles, la pente naturelle du terrain a été réduite par la construction de terrasses soutenues par des murs.

L’observation est effectuée entre 1996 et 1998. L’expérience a commencé avec des clones numérotés: 75, 95, 96 et 227 de la variété Chardonnay. Le porte greffe est le Kober 5 BB. La forme de conduite est le cordon. La taille est longue. La densité de plantation est 3,5 x 1 mètre (2857 ceps par 1/ha).