Quelles cibles moléculaires pourraient expliquer l’effet du terroir sur la composition des baies en sucres et acides?

While the trend in winemaking is toward reducing the inputs and especially sulphites, the development of While the trend in winemaking is toward reducing the inputs

The characterization of chemical compounds related with quality of grape must and wine is relevant for the viticulture and enology fields. Analytical methods used for these analyses require expensive instrumentation as well as a long sample preparation processes and the use of chemical solvents. On the other hand, near-infrared (NIR) spectroscopy technique is a simple, fast and non-destructive method for the detection of chemical composition showing a fingerprint of the sample. It has been reported the potential of NIR spectroscopy to measure some enological parameters such as alcohol content, pH, organic acids, glycerol, reducing sugars and phenolic compounds.

Valpolicella is an Italian region famous for the production of high quality red wines. Wines produced in its different sub-regions are believed to be aromatically different, as confirmed by recent studies in our laboratory. Aging is a very common practice in Valpolicella and it is required by the appellation regulation for periods up to four years. The aim of this study was to investigate the evolution, during aging, of volatile chemical composition of Valpolicella wines obtained from grapes harvested in different sub-regions during different vintages.

Dans les Charentes, en réponse à une crise de production du vignoble destiné à la production de Cognac, un plan de diversification viticole pour des vins de pays de qualité est mis en place. Il nécessite une connaissance des sols et de leurs caractéristiques viticoles pour orienter le choix des types de vins et adapter l’itinéraire technique de production.

Grapes (Vitis vinifera L.) are a fruit crop of high economic significance globally. Each grapevine cultivar is characterized by its distinctive grape aroma, affecting the wine quality. In several cultivars, the aroma is shaped by terpenoid (mono- and sesqui-terpenoids). Their profile is controlled by terpene synthases (TPS), which are part of a largely expanded gene family. How the variation in TPS copy number and sequence among cultivars determines terpenoid profiles of grapes remains largely unexplored. We annotated TPS in the haplotypes of seven genomes (Riesling, Albariño, Fiano, Gewürztraminer, Pinot Noir, Cabernet Sauvignon, and Viognier) using BLAST, GMAP, PFAM, and phylogenetic analyses. Further, TPS expression patterns and terpenoid accumulation during berry development and ripening were characterized using RNA-Seq and SPME/GC-MS platforms, respectively. Variation in TPS copy number exists among cultivars. Specifically, the TPS counts span a range of 251 to 150 for Riesling and Fiano, respectively, when considering combined haplotypes within each cultivar. Total terpenoid accumulation patterns throughout development were consistent among the five aromatic cultivars, marked by high concentrations in flowers, followed by a decline and subsequent rise during berry development and ripening, respectively. Conversely, non-aromatic cultivars exhibited no substantial increase in terpenoid concentration during ripening. Transcriptome and network analyses are currently employed to determine which TPS are expressed in the berry and determine the terpenoid profile of the specific cultivar. These findings shed light on the genomic determinants of grape aroma in major cultivars, and allow future studies focused on cultivar-specific responses of terpenoid biosynthesis to environmental stresses.