Deciphering the function and regulation of VviEPFL9 paralogs to modulate stomatal density in grapevine through New Genomic Techniques

The notion of «terroir» refers to the link between the composition, quality and taste of a wine, on the one hand, and its place of origin, on the other. It involves, among other things, the signature of soil elements, as well as the influence of climatic conditions and plant material used. The composition of the wine is also influenced by the winemaking, storage and bottling processes. We were lucky enough to have a time series of the same champagne, from the end of the first world war to the present. On this exceptional time series, we followed, with the most advanced methods, all the elemental signatures by isotopic multi-dilution, the evolution of the isotopic ratios of heavy elements with very high precision of Sr, Pb, B and Cu.

Oxygen management is crucial in terms of wine quality. Even more for white and rosé wines, which are less protected against oxidation than reds due to the lower levels of antioxidant polyphenols. This need is due to the existence of equilibria between chemical forms depending on the redox potential.

Wine consumers generally demand wines having a perception of softer tannins and less ripe, having a heaviness and richness on palate (full-body wine) with a limpid and stable color. However, polyphenol
(tannins)-rich wines have been also correlated with unpleasant taste properties such as astringency and
bitterness when perceived at high intensities. Modulating these unpleasant properties could be important for consumer’s approval of wines.

One of the limitations of vineyards in warm areas is the loss of wine quality due to higher temperatures during the grape ripening period. In order to adapt the vineyards to these new climatic conditions, a possible solution is to delay the ripening process of the grapes towards periods with milder temperatures, by means of management practices and thus improve the quality of the fruit and the wine produced. The technique of severe shoot pruning (SSP) has proven useful in achieving this objective.

Fruity notes play a key role in the consumer’s appreciation of Bordeaux red wines. If literature provides a lot of knowledge about the nature of volatile compounds involved in this fruity expression, the sensory phenomena involving these compounds in mixture still need to be explored. Considering previous sensory works about the impact of esters and some overripening compounds, the goal of this work was to study the implication of perceptual interactions involving red wine odorant compounds of diverse origins and described as potentially affecting fruity aromatic expression.