Investigation on harvesting period choices for correct interpretation of experimental results

Rotundone is the main aroma compound responsible for peppery notes in red wine. This positive and very potent molecule has an odor threshold of 8 ng/L in water and 16 ng/L in red wine. It has been detected in several grape varieties with some of the highest concentrations recorded in Syrah, Duras, Tardif and Noiret, an interspecific hybrid grown in the North-East of the USA. If several winemaking practices have been identified to lower rotundone in wine, up to date, no enological solution has proved its efficiency to maximize it. This means that efforts to produce high rotundone wines must be undertaken in vineyards. This work provides practical ways that can be used by winegrowers to modulate rotundone levels in their wines.

Studies on wineomics (wine’s metabolome) have increased considerably over the last two decades. Wine results from many environmental, human and biological factors leading to a specific metabolome for each terroir. NMR metabolomics is a particularly effective tool for studying the metabolome since it allows the rapid and simultaneous detection of major compounds from several chemical families.1 Quantitative NMR has already proven its effectiveness in monitoring the authenticity of still wines.

Vineyards harbor a myriad of microorganisms that interact with each other and with the grapevines. Some microorganisms are plant pathogens, such as the oomycete Plasmopara viticola that causes grapevine downy mildew. Others, such as plant growth promoting bacteria and disease biocontrol agents, have a positive influence on vine health. The present study aims to (1) investigate whether vine-based culture media increase the cultivability of the grapevine microbiota, in comparison to standard culture media and (2) identify and isolate bacterial taxa naturally present in grapevine leaves and significantly more abundant in plots showing low susceptibility to downy mildew.

Although the ripening process of grapevine berries is well-documented at the vineyard level, pinpointing distinct developmental stages remains challenging. The asynchronous development of berries results in dynamic biases and metabolic chimerism. It is thus crucial to consider individual berries separately and resynchronize their internal clock for deciphering physiological changes throughout development. Given the importance of grape composition in wine quality, we aimed at measuring developmental changes in the metabolome of Syrah single berries from anthesis to over-ripening, without a priori preconceived.

Climate change and an evolving environmental and societal context call for the exploration of disease-resistant and/or drought-adapted grape varieties that meet the demands of consumers and society.