Research summary on the use of Terroir as a wine purchasing cue

The wine industry widely recognizes that early-harvested grapes or those with uneven ripeness at harvest can produce wines with an “unripe fruit” mouthfeel [1,2]. Despite this, it is still unknown which compounds cause these sensory flaws or the most effective winemaking techniques to address them.

One of the major determinants of wine quality is the aroma. Wine aroma is the human perception of the matrix of grape and yeast derived volatiles and their interaction that contribute to flavour wine. Most common are higher alcohols, ester and aldehydes. In previous studies the formation of characteristic volatile compounds have been linked to the metabolism of branched-chain and aromatic amino acids
(BCAAs) in synthetic grape must. Here we report on an investigation to assess the impact of the initial amino acid concentration on the production of aroma compounds by the industrial yeast VIN13 grown in both synthetic and real grape musts.

Rootstocks were the first sustainable and environmentally friendly strategy to cope with a major threat for Vitis vinifera cultivation. In addition to providing Phylloxera resistance, they play an important role in protecting against other soil-borne pests, such as nematodes, and in adapting V. vinifera to limiting abiotic conditions. Today viticulture has to adapt to ongoing climate change whilst simultaneously reducing its environmental impact. In this context, rootstocks are a central element in the development of agro-ecological practices that increase adaptive potential with low external inputs. Despite the apparent diversity of the Vitis genus, only few rootstock varieties are used worldwide and most of them have a very narrow genetic background. This means that there is considerable scope to breed new, improved rootstocks to adapt viticulture for the future.

In the face of climate change, new grapevine varieties will have to show an adaptive phenotypic plasticity to maintain production with erratic water resources, and still ensure the quality of the final product. Their selection requires a better knowledge of the genetic basis of those traits and of the elementary processes involved in their variability. ‘PlastiVigne’, an emblematic project of the Vinid’Occ key challenge, funded by the Occitanie Region (France), tackles this issue with innovative genomic and physiological tools implemented on a unique panel of grape genetic resources representing the genetic diversity of Vitis vinifera. A graph-pangenome is developed from a representative set of high-quality genomes to study the extent and impact of structural genome variations and chromosomal rearrangements in the rapid adaptation capacity of grapevine.

The postharvest dehydration of grapes is a traditional practice to obtain wines with unique traits (e.g. sweet, dry/reinforced). The modern facilities (dehydrating rooms) used for this purpose are equipped with systems for artificially controlling the inside environment parameters, to obtain the desired dehydration kinetic and preserve the grapes from grey mold (Botrytis cinerea) infection, However, the conditioning systems are extremely energy-demanding and the identification and practical applications of solutions effective in controlling/reducing the postharvest decay would reduce the costs of the operation of the dehydration facilities. To this end, we explored the potential of ozone-based treatments on harvested grapes and preliminarily tested if the treatment could impact the normal behavior and metabolism of grapes during the traditionally slow dehydration practice.