Grape genetic research in the age of pangenomes

Obiettivo del progetto è la valutazione dell’influenza climatica e pedologica dell’areale di Montefalco sul vitigno Sagrantino, ponendo particolare attenzione alla componente polifenolica e antocianica. Sono stati quindi messi a confronto, a partire dal 2001 fino al 2008, sei differenti zone tutte situate all’interno dell’areale DOCG Sagrantino di Montefalco; per ciascun vigneto alla vendemmia sono state effettuate analisi sui parametri analitici e sul contenuto polifenolico e antocianico delle uve. Ognuna delle sei zone è inoltre stata caratterizzata dal punto di vista pedoclimatico, valutando l’influenza del clima e della tipologia di suolo sui parametri analitici presi in considerazione.

In a highly competitive worldwide market, a current challenge for the beverage sector is to diversify the range of products and to offer wines and spirits with typicity and character.

During alcoholic fermentation, wine yeasts generate a large variety of volatile metabolites, including acetate esters, ethyl fatty acid esters, higher alcohols, volatile fatty acids and volatile sulfur compounds that contribute to the aroma profile of wine. These molecules, refered as fermentative aromas, are the most abundant volatile compounds synthetized by yeasts and the metabolic pathways involved in their formation have been well characterized. Furthermore, other molecules with a major organoleptic impact may be produced during wine fermentation including terpene derivatives. However, little information is available on the contribution of yeasts to the formation of these molecules, in particular on their ability to synthethise de novo the terpens derivatives or to produce hydrolytic enzymes involved in the release of varietal precursors.

Hillside vineyards have a great potential to produce world class wines. The unique microclimate lead to the production of rich, flavory wines.

The current climate changes are directly threatening the balance of the vineyard at harvest time. The maturation period of the grapes is shifted to the middle of the summer, at a time when radiation and air temperature are at their maximum. In this context, the implementation of corrective practices becomes problematic. Unfortunately, our knowledge of the climate effect on the quality of different grape varieties remains very incomplete to guide these choices. During the Innovine project, original experiments were carried out on Syrah to study the combined effects of normal or high air temperature and varying degrees of exposure of the berries to the sun. Berries subjected to these different conditions were sampled and analyzed throughout the maturation period. Several quality characteristics were determined, including anthocyanin content. The objective of the experiments was to investigate which climatic determinants were most important for anthocyanin accumulation in the berries. Temperature and irradiance data, observed over time with a very thin discretization step, are called functional data in statistics. We developed the procedure SpiceFP (Sparse and Structured Procedure to Identify Combined Effects of Functional Predictors) to explain the variations of a scalar response variable (a grape berry quality variable for example) by two or three functional predictors (as temperature and irradiance) in a context of joint influence of these predictors. Particular attention was paid to the interpretability of the results. Analysis of the data using SpiceFP identified a negative impact of morning combinations of low irradiance (lower than about 100 μmol m−2 s−1 or 45 μmol m−2 s−1 depending on the advanced-delayed state of the berries) and high temperature (higher than 25oC). A slight difference associated with overnight temperature occurred between these effects identified in the morning.

The sustainability of viticulture hinges on maintaining quality and yield while reducing pesticide use. Promising strides in this direction involve the development of clones with enhanced disease tolerance, particularly through the knockout of plant susceptibility genes. Knocking out of Downy Mildew Resistant 6 (DMR6) led to increased levels of endogenous salicylic acid (SA), a regulator of immunity, resulting in enhanced tolerance to Downy Mildew (DM) and other diseases in various crops.