Characterization of Brettanomyces bruxellensis biofilm, a resistance strategy to persist in wine-related environments

Considérant d’une part la judicieuse mise au point d’un label de qualité contrôlée des miels suisses (STÖCKLI et al. 1997), considérant d’autre part l’élaboration d’une carte des paysages végétaux (HEGG et al. 1993),

In this video recording of the IVES science meeting 2023, Sara Bernardo (CITAB, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal) speaks about understanding vine response to Mediterranean summer stress for the development of adaptation strategies – in the kaolin case. This presentation is based on an original article accessible for free on OENO One.

Depuis un an, nous essayons de mettre en place un projet de développement socio-économique et culturel d’une zone située essentiellement au sud de la Garonne et à cheval sur 3 départements (le Lot et Garonne, le Gers et le Tam et Garonne) et sur 2 régions (l’Aquitaine et Midi Pyrénées): le pays du Brulhois, “porte de la Gascogne”.

AIM: Since 2012 the Veneto Region regulation (north-east Italy) allowed wine production using 20 hybrid grapevine varieties selected for their high tolerance to downy mildew and powdery mildew. Characterized by vigour, high grape productivity and low pesticide use, these varieties are suitable to develop sustainable viticulture in mountain areas located at medium altitudes.

Late spring frost is a major challenge for various winegrowing regions across the world, its occurrence often leading to important yield losses and/or plant failure. Despite a significant increase in minimum temperatures worldwide, the spatial and temporal evolution of spring frost risk under a warmer climate remains largely uncertain. Recent projections of spring frost risk for viticulture in Europe throughout the 21st century show that its evolution strongly depends on the model approach used to simulate budburst. Furthermore, the frost damage modelling methods used in these projections are usually not assessed through comparison to field observations and/or frost damage reports.
The present study aims at comparing frost risk projections simulated using six spring frost models based on two approaches: a) models considering a fixed damage threshold after the predicted budburst date (e.g BRIN, Smoothed-Utah, Growing Degree Days, Fenovitis) and b) models considering a dynamic frost sensitivity threshold based on the predicted grapevine winter/spring dehardening process (e.g. Ferguson model). The capability of each model to simulate an actual frost event for the Vitis vinifera cv. Chadonnay B was previously assessed by comparing simulated cold thermal stress to reports of events with frost damage in Chablis, the northernmost winegrowing region of Burgundy. Models exhibited scores of κ > 0.65 when reproducing the frost/non-frost damage years and an accuracy ranging from 0.82 to 0.90.
Spring frost risk projections throughout the 21st century were performed for all winegrowing subregions of Bourgogne-Franche-Comté under two CMIP5 concentration pathways (4.5 and 8.5) using statistically downscaled 8×8 km daily air temperature and humidity of 13 climate models. Contrasting results with region-specific spring frost risk trends were observed. Three out of five models show a decrease in the frequency of frost years across the whole study area while the other two show an increase that is more or less pronounced depending on winegrowing subregion. Our findings indicate that the lack of accuracy in grapevine budburst and dehardening models makes climate projections of spring frost risk highly uncertain for grapevine cultivation regions.