Genetic determinism of grapevine development stages as a tool for the adaptation to climate change

The application of different winemaking techniques helps to modify the basic parameters, phenolic profile, and aroma components influencing the final wine quality. In particular, pre-fermentative processes aim to increase the extraction and preservation of grape native compounds. Among them, cold liquid stabulation (macération sur bourbes) consists in maintaining the grape juice on its lees, in suspended condition at low temperature (0-8 °C) for a variable time (generally from 7 to 21 days). The aim of this work is to apply the cold liquid stabulation on two Italian white grape varieties, Arneis and Cortese, to evaluate the impact on basic parameters, color, polyphenolic compounds (TPI), antioxidant power (DPPH), total polysaccharides, and free and glycosylated volatile compounds (GC-MS analysis) during and after the process.

Grapevine is subject to multiple stresses, either biotic or abiotic, frequently in combination. These stresses may negatively impact the health status of plants and reduce yields. For biotic stress, grapevine is affected by numerous pest and diseases such as downy and powdery mildews, grey mold, black rot, grapevine fanleaf virus and trunk diseases (namely GTDs). The interaction between grapevine and pathogens is relatively complex and linked to various pathogenicity factors including cell-wall-degrading enzymes (especially CAZymes) and phytotoxic secondary metabolites, growth regulators, effectors proteins, and fungal viruses.

Amino acids play a crucial role in determining grape and wine quality [1]. Recently, research has suggested their metabolism is key to plant abiotic stress tolerance [2]. Therefore, the study of amino acid accumulation in grape berries and its response to environmental factors is of both scientific and economic importance.

The contribution of sulfur compounds to wine aroma has been studied for several years, as their role can be either positive, contributing to the fruitiness and typicity of some white wines like Sauvignon blanc, or negative when related to off-flavours caused by H2S.

The use of pectinolytic enzymes in winemaking is state of the art. These enzymes catalyse the degradation of pectic substances through depolymerization (hydrolases and lyases) and de-esterification. As a result, it supports the extraction of juice and facilitates filtration. It has also been shown in winemaking that the presence of pectinolytic enzymes improves the stability, taste, texture, colour and aroma of products. With regard to enzymes currently applied in winemaking, enzymes derived from filamentous fungi dominate the enzyme industry. Fungal-based pectinolytic enzymes specifically require purification from the culture medium to eliminate unwanted side reactions, which is poorly sustainable. Some non-traditional yeast strains have been reported to exhibit pectinolytic activities. Therefore, the direct use of pectinolytic yeast during wine fermentation process can be an attractive and alternative source for the use of enzymes as input.