Mining microbiome data to identify antagonists of grapevine downy mildew (Plasmopara viticola)

Depuis 1973, une commission statutaire administre la législation qui régit le zonage vitivinicole en Afrique du Sud. La province «Le Cap de l’ouest» cerne toutes les zones viticoles sauf quatre unités. Pour la plupart, le Cap de l’ouest a un climat méditerranéen. Les zones viticoles – qui produisent les «vins d’origine» – sont des régions, des districts, des quartiers et des domaines. Les régions sont vastes, séparées par la topographie, par ex. des chaînes de montagnes et des fleuves. Généralement, chaque région représente une zone climatique. Le climat de chaque district est plus homogène. Les quartiers sont exactement délimités par le climat, la topographie et la géologie. Les domaines sont les plus petits. Chaque domaine doit avoir un seul propriétaire.

Global warming is shifting vine phenology, resulting in a decoupling of phenolic and technological berry ripening. This is altering the balance of fruit traits, which is key relevance to winegrowers

Chemical studies aiming at assessing how a wine reacts towards oxidation usually focus on the characterization of wine constituents, such as polyphenols, or oxidation products. As an alternative, the key oxidation intermediate hydrogen peroxide H2O2 has never been quantified, although it plays a pivotal role in wine oxidation. H2O2 is obtained from molecular oxygen as the result of a first cascade of oxidation reactions involving metal ions and polyphenols. The produced H2O2 then reacts in a second cascade of oxidation to produce reactive hydroxyl radicals that can attack almost any chemical substrate in wine.

In order to study the impact of climate change on Bordeaux grape varieties and to assess the adaptation capacities of candidates to the grape varieties of this wine region to the new climatic conditions, an experimental block design composed of 52 grape varieties was set up in 2009 at the INRAE Bordeaux Aquitaine center. Among the many parameters studied, the three main phenological stages of the vine (budburst, flowering and veraison) have been closely monitored since 2012. Observations for each year, stage and variety were carried out on four independent replicates. Precocity indices have been calculated from the data obtained over the 2012-2021 period (Barbeau et al. 1998). This work allowed to group the phenological behaviour of the grapevine varieties, not only based on the timing of the subsequent developmental stages, but also on the overall precocity of the cycle and the total length of the cycle between budburst and veraison. Results regarding the variability observed among the different grape varieties for these phenological stages are presented as heat maps.

Water use efficiency is one of the most valued objectives in vine growing in mediterranean climates (de la fuente et al., 2015). Due to this, the grape growers provide different adaptation strategies according to their efficient consumption against the presumable water deficit generated under these environmental conditions. The use of non-positioned shoot systems (like sprawl, bush, etc.) Can help to achieve this objective.