Metatranscriptomic analysis of “aszú” berries: the potential role of the most important species of the grape microbiota in the aroma of wines with noble rot

During red wine fermentation, the extraction of phenolics compounds and sufficient oxygen provision are critical for wine quality [1,2]. In this trial, we aimed at evaluating the kinetics of phenolic extraction and dissolved oxygen during red wine fermentations using the airmixing system. Twenty lots of red grape musts were fermented in 300.000 L tanks, equipped with airmixing, using two injection regimes (i.e., high and low intensity, and high and low daily frequency). An oxygen analyzer was introduced into the tanks in order to record the concentration of dissolved oxygen over time.

Bobal is the second most widely grown Spanish red grape variety (54,165 has), mainly cultivated in the Valencian Community and especially, in Utiel-Requena region (about 67% of 34,000 has). In this study, agronomic and enological parameters were determined in 98 biotypes selected during 2018 and 2019 in more than 50 vineyards over 50 years-old in the Utiel-Requena region. Moreover, a multi-criteria approach considering temperature and rainfall (Fig. 1A), among other parameters, was made to establish three different zones within the region (Fig. 1B), where in the future the selected biotypes will evaluated. In fact, in 2020, 4 replicates and 12 vines per biotype were planted in an experimental vineyard to preserve this important intra-cultivar diversity.

Light is a fundamental part at sales points which influences in the conservation of wines, particularly in those that are sold in transparent glass bottles such as rosé wines and increasingly white wines. The photochemical effect known as “light-struck taste” can cause changes in the aromatic characteristics of the wine. This “light-struck taste” is due to reactions triggered by the photochemical sensitivity of riboflavin (RBF).

In order to study the impact of climate change on Bordeaux grape varieties and to assess the behavior of candidate grape varieties potentially better adapted to the new climatic conditions, an experimental vineyard composed of 52 grape varieties was planted in 2009 at the INRAE Bordeaux Aquitaine center[1]. Among the many parameters studied since 2012, berry weight for each variety was measured weekly from mid-veraison to maturity, with four independent replicates. The kinetics obtained allowed to study berry growth, a key parameter in grape composition and yield.

The foliar application of urea has been shown to be able to satisfy the specific nutritional needs of the vine as well as to increase the nitrogen composition of the must. On the other hand, the use of nanotechnology could be of great interest in viticulture as it would help to slow down the release of urea and protect it against possible degradation. Several studies indicate that cell wall synthesis and remodeling are affected by nitrogen availability.