Using multifactorial analysis to evaluate the contribution of terroir components to the oenological potential of grapes at harvest

The recent development of regulatory genomics has raised increasing interest in plant research since transcriptional regulation of genes plays a pivotal role in many biological processes. By shedding light on the target genes of the various transcription factors (TFs), it is therefore possible to infer the influence they exert on the different molecular mechanisms. In this regard, the attention was focused on WRKYs, a family of TFs almost exclusively found in plant species. In grapevine, WRKYs are involved in several biological processes, playing a key role in berry development, hormonal balance and signalling, biotic and abiotic stresses responses, and secondary metabolites biosynthesis.

The objective of the present work is to investigate wine produced from dehydrated grapes and vinified according to classical Roman manuals.

METHODS – Locally produced Muscat of Alexandria’s grapes were used for the sweet wine production, grown in the experimental vineyard of Instituto Superior de Agronomia (Lisbon, Portugal). The grapes were harvested manually slightly over-ripe and subjected to greenhouse drying. After 7-10 days dried grapes were transported to an experimental winery for various operations (e.g., grape weighing, sorting, crushing/destemming). Several maceration protocols were used comprising the addition of saltwater and white wine to whole bunches or destemmed grapes. Fermentation was conducted with the addition of commercial yeast. The standard physico-chemical parameters of wines were determined according to the OIV standards.

In wine producing regions around the world, climate change has the potential to decrease the frequency and amount of precipitation and increase average and extreme temperatures. This will lower soil water availability and increase evaporative demand, thereby increasing the frequency and intensity of water deficit experienced in vineyards. Among other things, grapevines manage water deficit by regulating stomatal closure. The dynamics of this regulation, however, have not been well characterized across the range of Vitis vinifera cultivars. Providing a method to understand how different cultivars regulate their stomata, and hence water use in response to changes in soil water deficits will help growers manage vineyards and select plant material to better meet quality and yield objectives in a changing climate.

The identification and management of intra-vineyard variability are key to precision viticulture, and sensors have been proven to be highly efficient tools for detecting these variations.

The light exposure of wine can be detrimental as a relevant loss of aromas takes place [1] and light-induced reactions can occur. The latter involves riboflavin (RF), a photosensitive compound, that is fully reduced by acquiring two electrons. When the electron-donor is methionine, the light-struck taste (LST) can appear leading to cooked cabbage, onion and garlic odours-like [2]. The use of oenological tannins can limit the appearance of LST in both model wine [3] and white wine [4]. This research aimed to evaluate the impact of certain oenological tannins, selected in a previous study as the most effective against LST [5], in both white and rosé wines.