Un exemple de valorisation d’une étude de terroir au sein d’une unité coopérative de production à Saint Hilaire d’Ozilhan (Gard) dans les cotes du Rhône

‐Evaluation of xylem embolism is an important challenge in identifying drought tolerant genotypes within the context of climate change.

In recent years, the consumption of fine wines in Brazil has increased significantly, a phenomenon that is also reflected in the expansion of production to new regions. In the brazilian southeast for example, the so-called “winter wines” are being produced, through management in two cycles, one of formation and one of production, with two prunings and one harvest per year, a technique known as double pruning, with vineyards established at altitudes close to or above 1,000 m above sea level.

Two treatments were studied in vines of cv. Tempranillo blanco (Vitis vinifera L.) during the 2012-2018 period in an experimental plot located in Rincón de Soto (La Rioja, Spain). Rainfed treatment (R0) was compared with respect to an irrigation treatment (R2) equivalent to 30% of the crop evapotranspiration (ET0) from fruitset to harvest phenological stages. Pre-veraison irrigation ranged from 43 (2014) to 66 mm/m2 (2018) while post-veraison irrigation ranged from 37 (2017) to 115 mm/m2 (2012).The normalized difference vegetation index (NDVI) was assessed by measures of reflectance, nutrients were determined by analysis of petioles sampled at veraison, grape production was determined at harvest as well as renewable wood weight was assessed at pruning time.

Epidermal Patterning Factors are a class of cysteine rich peptides known to be involved in many developmental processes. The role of EPF1, EPF2 and EPFL9 in controlling leaf stomata formation has been well described in model plants and cereals, and recently also in grapevine, while little is known about their activity in other organs. The aim of our study is to investigate whether VviEPFL9-2 can have a specific biological function in grapevine roots, where it resulted to be expressed. As grapevine is cultivated in the form of a grafted plant, we focused our study on the commonly used rootstock Kober 5BB (Vitis berlandieri x Vitis riparia). VviEPFL9-2 was edited in Kober 5BB plants using Agrobacterium tumefaciens transformation of embryogenic calli and the CRISPR/Cas9 technology. The phenotypic evaluation in greenhouse indicated that, as expected, the leaves of knock-out (KO) plants have a significant lower stomatal density compared to WT, associated with a lower stomatal conductance.

Sulfites (SO2) addition during winemaking is a widespread practice worldwide. This addition is realized at different steps of the winemaking due to the antimicrobial and antioxidant capacity of SO2. In a context of understanding white wines oxidative stability, knowledge about the impact of SO2 on the wine molecular diversity, especially compounds involved in the antioxidant capacity of wine, appears to be very important. In recent years, some studies have shown that SO2 can react with a large number of wine compounds resulting in the formation of numerous adducts. The diversity of compounds involved is important including in particular pyruvic acid, 2-keto-glutaric acid, glyceraldehyde, sugar, phenolics compounds but also amino acids or peptides. Moreover Roullier-Gall et al. have shown using FT-ICR-MS analysis that the molecular composition of wines remains impacted by addition of SO2 to the must (0, 4 and 8 g/hL SO2), several years after winemaking. Indeed, wines made from protected must (8g/hL SO2) contain a larger diversity of CHOS and CHONS compounds than wines made from unprotected must (0 g/hL SO2). The study of the impact of glutathione addition on the sensory oxidative stability has further shown that CHOS and CHONS compounds (amino acids, aromatic compounds and peptides) are markers of the antioxidant metabolome of white wines. This suggests that CHOS and CHONS compounds arise from SO2 adducts formation but also from a protecting effect of SO2 on the antioxidant metabolome of white wines.