Exploring the regulatory role of the grapevine MIXTA homologue in cuticle formation and abiotic stress resilience

Alcoholic fermentation conducted by microorganism is a key step in the production of wine. In this process, interactions between different species of yeast are widely described but their mechanisms are still poorly understood. The interactions studied in wine are mainly between Saccharomyces and non-Saccharomyces species. Therefore, little is known about the mechanisms of interactions

In wine growing regions around the world, climate change has the potential to affect vine transpiration and overall vineyard water use due to related changes in atmospheric demand and soil water deficits. Grapevines control their transpiration in response to a changing environment by regulating conductance of water through the soil-plant-atmosphere continuum. Most vineyard water use models currently estimate vine transpiration by applying generic crop coefficients to estimates of reference evapotranspiration, but this does not account for changes in vine conductance associated with water stress, nor differences thought to exist between varieties. The response of bulk stomatal conductance to daily weather variability and seasonal drought stress was studied on Cabernet-Sauvignon, Merlot, Tempranillo, Ugni blanc, and Semillon vines in a non-irrigated vineyard in Bordeaux France. Whole vine sap flow, temperature and humidity in the vine canopy, and net radiation absorbed by the vine canopy were measured on 15-minute intervals from early July through mid-September 2020, together with periodic measurement of leaf area, canopy porosity, and predawn leaf water potential. From this data, bulk stomatal conductance was calculated on 15-minute intervals, and multiple regression analysis was performed to identify key variables and their relative effect on conductance. Attention was focused on addressing multicollinearity and time-dependency in the explanatory variables and developing regression models that were readily interpretable. Variability of vapor pressure deficit over the day, and predawn water potential over the season explained much of the variability in conductance, with relative differences in response coefficients observed across the five varieties. By characterizing this conductance response, the dynamics of vine transpiration can be better parameterized in vineyard water use modeling of current and future climate scenarios.

Understanding how different pedoclimatic conditions interact with vine and berry physiology, and subsequently impact wine quality, is paramount for an good valorization of viticultural terroirs and can help to optimize mitigation strategies in the face of global warming

Chitosan is a biopolymer industrially obtained from the deacetylation of chitin, the second most abundant polysaccharide on earth, after cellulose. It is extracted from various terrestrial and marine resources, including insects, grasshoppers, shrimps, crabs, lobsters, squids, and fungi. chitosan has a polycationic character due to the free amine groups along its chemical backbone, and depending on its deacetylation degree (DD) and molecular weight (MW), it shows variable properties that differ from those of other natural polysaccharides.

The concept of ‘terroir’ describes the interplay of the environmental factors that affect the grapevine. This includes but is not limited to climate, soil composition, vineyard management, topography, and geology.