Unravelling Saccharomyces cerevisiae biosynthethic pathways of melatonin, serotonin and hydroxytyrosol  by UPLC-HRMS Isotopic labelling analysis

By dissecting the root system architecture (RSA) into its underpinning components (e.g. root emission, axial growth, radial growth, branching, root direction or tropism) and identifying the relationships between them, functional-structural 3D root models are promising tools for analyzing the diversity and complexity of root system phenotypes with Genotype × Environment interactions. The model parameters are assumed to be synthetic traits, less influenced by the environment, and consequently with less polygenic architectures than the integrative RSA traits they drive. Root models can serve as a basis for in silico development of root system ideotypes by highlighting the developmental processes and parameters that most likely influence RSA fitness.

In wine growing regions around the world, climate change has the potential to affect vine transpiration and overall vineyard water use due to related changes in atmospheric demand and soil water deficits. Grapevines control their transpiration in response to a changing environment by regulating conductance of water through the soil-plant-atmosphere continuum. Most vineyard water use models currently estimate vine transpiration by applying generic crop coefficients to estimates of reference evapotranspiration, but this does not account for changes in vine conductance associated with water stress, nor differences thought to exist between varieties. The response of bulk stomatal conductance to daily weather variability and seasonal drought stress was studied on Cabernet-Sauvignon, Merlot, Tempranillo, Ugni blanc, and Semillon vines in a non-irrigated vineyard in Bordeaux France. Whole vine sap flow, temperature and humidity in the vine canopy, and net radiation absorbed by the vine canopy were measured on 15-minute intervals from early July through mid-September 2020, together with periodic measurement of leaf area, canopy porosity, and predawn leaf water potential. From this data, bulk stomatal conductance was calculated on 15-minute intervals, and multiple regression analysis was performed to identify key variables and their relative effect on conductance. Attention was focused on addressing multicollinearity and time-dependency in the explanatory variables and developing regression models that were readily interpretable. Variability of vapor pressure deficit over the day, and predawn water potential over the season explained much of the variability in conductance, with relative differences in response coefficients observed across the five varieties. By characterizing this conductance response, the dynamics of vine transpiration can be better parameterized in vineyard water use modeling of current and future climate scenarios.

Teran is an important native variety grown in Istria known for its high level of polyphenols and intensive fruity character of wines. Teran’s yield and wine typicity have recently decreased due to climate changes (increased temperature and severe drought). Four drip irrigation treatments (25%, 50%, 75%, 100% of total evapotranspiration) and control were investigated for the influence on Teran yield and quality, where focus was given to the content and composition of main polyphenolic and volatile compounds in grapes. Irrigation positively influenced yield since the berry weight also increased with increased irrigation. This resulted in the highest yield for 100% ETc. The highest concentration of polyphenols had control, while the irrigation treatments did not differ significantly. However, there was a tendency to decrease concentration with increased irrigation probably due to the increased berry size, which led to a dilution effect. Regarding the volatile compounds, the most abundant group was alcohols, followed by acids.

The mechanisms behind thiol precursor accumulation in grapes remain incompletely understood, nor are the ways in which they can be improved by agronomic practices. A six-year field trial studied the physiological response of the Swiss white cultivar Vitis vinifera Arvine, rich in varietal thiols and precursors, to canopy management, i.e. leaf removal and canopy height.. Five treatments were set up in a randomized block design to assess the impacts of 1) pre-flowering LR (i.e. pre-flowering or full-flowering stages) and 2) compensating for the leaf area removed in the cluster zone by increasing the trimming height (i.e. 100 or 150 cm canopy height), compared with a non-defoliated control treatment.
Intensive pre-flowering LR severely reduced yield potential (–47% on average) and reduced the concentration of 3-mercaptohexanol precursors (P-3MH) in the must (–21%; p-value < 0.10).

L’étude des relations Terroir – Vigne – Raisin est complexe. La recherche et le développement des facteurs qualitatifs qui influencent le caractère des vins sont multiples. Divers travaux mettent en évidence la relation entre l’alimentation en eau de la plante, son développement végétatif et les caractéristiques de ses raisins.