Exploring the inner secrets of grapevine: a journey through plant-microbe interactions

Rotundone is the main aroma compound responsible for peppery notes in wines whose biosynthesis is negatively affected by heat and drought. Through the alteration of precipitation regime and the increase in temperature during maturation, climate change is expected to affect wine peppery typicality. In this context there is a demand for developing sustainable viticultural strategies to enhance rotundone accumulation or limit its degradation. It was recently proposed that ultraviolet (UV) radiations could stimulate rotundone production. The aim of this study was to investigate under field trial conditions the impact of grape exposure and UV treatments on rotundone in Vitis vinifera L. Tardif, an almost extinct grape variety from south-west France that can express particularly high rotundone levels. Four different treatments were compared in 2021 to a control treatment using a randomised complete block design with three replications per treatment. Grape exposure was manipulated through early or late defoliation. Leaf and laterals shoots were removed at Eichorn Lorenz growth stages 32 or 34 on the morning-sun side of the canopy. During grape maturation, UV radiations were either reduced by 99% by installing UV radiation-shielding sheets, or applied four times using the Boxilumix™ non thermal device (Asclepios Tech, Tournefeuille) with the aim of activating plant signalling pathway. Loggers displayed in solar radiation shields were used to assess the effect of such shielding sheets on air temperature within the bunch zone. The composition of grapes subjected to these treatments will be soon analysed for their rotundone content and basic classical laboratory analyses. Grapes will be harvested to elaborate wines under standardized small-scale vinification conditions (60kg) that will be assessed by a trained sensory panel.

The most recent methodological developments in soil survey and land evaluation, that can be taken as reference in the viticultural field, go over usage of the GIS and database. These informatic tools, which begin to be widely utilised, consent to realise evaluations at different geographic scale and with different data quality and quantity in entrance.

To test the hypothesis that soil type plays a minor role relative to that of vine vigor in the determination of yield, fruit composition and wine sensory attributes, 5 Chardonnay vineyards in the Niagara

The Cognac region is expanding, driven by the success of its renowned brandy and the demand for high grape yields to ensure a steady supply of base wine for distillation. Ugni blanc, the most widely planted grape variety, relies on rootstocks for soil and climate adaptation, providing essential nutrient supplies to the scion. Understanding the impact of rootstocks on key berry components, such as sugars and nitrogen compounds, is crucial. These compounds serve as primary precursors for the production of fermentative aroma metabolites, which, in turn, act as quality indicators for eau-de-vie.

A terroir can be defined as a natural unit that is characterised by a specific agricultural potential, which is imparted by natural environmental features, and is reflected in the characteristics of the final product.