Exploring the prevalence of esca-induced leaf symptoms in French vineyards and the role of climate: a national scale analysis

The production of most red wines that are sold involves an alcoholic fermentation carried out by yeasts of the Saccharomyces genus, and a subsequent fermentation carried out by lactic bacteria of the Oenococus oeni species after the first one is fully completed. However, the traditional process can face complications, which can be more likely in grape juices with high levels of sugar and pH. Because of climate change, these situations are more frequent in the wine industry. The main hazards in those scenarios are halts or delays in the alcoholic fermentation or the growth of unwanted bacteria while the alcoholic fermentation is not done yet and the wine still has residual sugars.

A large population of vines of the Mandón minority red variety (synonymous with Garró) has been located in old vineyards of the D.O. Arribes (Zamora and Salamanca) to conserve and recover this minority variety. The wines made with this variety are characterized by their good structure and color, interesting harmony, an excellently low pH, with high acidity, as well as complex aromas of blue fruits and a marked and expressive minerality.

The appearance of the Phylloxera pest in the 19th century in Europe caused dramatical damages in grapevine diversity. To mitigate these losses, grapevine growers resorted to using crosses of different Vitis species, such as 110 Richter (110R) (V. berlandieri x V. rupestris), which has been invaluable for studying adaptations to stress responses in vineyards. Recently, a high quality chromosome scale assembly of 110R was released, but the available gene models were predicted without using as evidence transcriptional sequences obtained from roots, that are crucial organs in rootstock, and they may express certain genes exclusively. Therefore, we employed RNA sequencing reads of 110R roots under different stress conditions to predict new gene models in each haplotype of 110R under different stresses.

The presence of acetic acid bacteria in wine can lead to the appearance of acetic acid at concentrations above the perception threshold, causing the wine rejection by the consumer. During the winemaking process, avoiding the presence of acetic acid bacteria is very difficult, as there is always a residual population accompanying the wine[1], and the problem arises with the significant development of these microorganisms that metabolizes large amounts of acetic acid.
The concern of wineries to control the presence of acetic acid bacteria in wines during their conservation is due to the absence of simple and effective analyses that allow the detection of these microorganisms in the initial stages.

Vineyards from mild temperature, high humidity locations receive often treatments with fungicides to prevent damages produced by fungi responsible for mildium, oidium and botrytis infections. In addition, insecticides are also applied to vineyards to fight again pests, which affect directly, or indirectly (as vectors of different diseases), their productivity. A fraction of the above compounds reaches the soil of vineyards, either during application, or when released from the canopy of vines due to rain-wash-off. Thereafter, depending on soil conditions (pH, organic matter) and environmental variables (regimen of rain, slope of vineyards), they might persist in this compartment, be degraded and/or transferred to water masses, modifying the biodiversity of soils and/or affecting the quality of water reservoirs.