Chitosan is an environmentally-friendly active molecule that has been explored for numerous agricultural uses. Its use in crop protection is well-known, however, other properties, such as bioactivity, deserve attention. Moreover, the modes of actions of chitosan remain to be elucidated. The present study assessed the levels of total phenolic compounds, the antioxidant potential, and the expression of reactive oxygen species (ROS) scavenging genes in the berries (skins and seeds), leaves, cluster stems, and shoots upon chitosan application on two red grapevine varieties (Touriga Franca and Tinto Cão). The application of chitosan on the whole vine before and after veraison led to the increased levels of polyphenols, anthocyanins, and tannins in Tinto Cão berries, and polyphenols and tannins in Touriga Franca berries, respectively. CUPric Reducing Antioxidant Capacity (CUPRAC) and Ferric Reducing Antioxidant Power (FRAP) assays indicated an increase in the antioxidant potential of berries. With the exception of ascorbate peroxidase (APX), all the ROS pathway genes tested, i.e., iron-superoxide dismutase (Fe-SOD), copper-zinc-superoxide dismutase (Cu/Zn-SOD), catalase (CAT), glutathione reductase (GR), glutaredoxin (Grx), respiratory burst oxidase (Rboh), amine oxidase (AO), peroxidase (POD) and polyphenol oxidase (PPO), were found up-regulated in chitosan-treated berries. Results from the analyses of leaves, stems, and shoots revealed that chitosan not only induced the synthesis of phenolic compounds but also acted as a facilitator for the transfer of polyphenols from the leaves to the berries.

More than 100 grapevine varieties are registered as suitable for wine production in “Douro” and “Trás-os-Montes” Protected Designations of Origin regions; however, only a few are actually used for winemaking. The identification of varieties cultivated in past times can be an important step to take advantage of all the potential of these regions grape biodiversity. The conservation of the vanishing genetic resources boosts greater product diversification, and it can be considered strategic in the valorisation of these wine regions. Hence, one goal of the present study was to prospect and characterise, through molecular markers, 310 plants of 11 old vineyards that constitute a broad representation of the grape genetic patrimony of “Douro” and “Trás-os-Montes” wine regions; 280 samples, grouped into 52 distinct known varieties, were identified through comparison of their genetic profiles generated via 6 nuclear SSR and 43 informative SNP loci amplification; the remaining 30 samples, accounting for 13 different genotypes, did not match with any profile in the consulted databases and were considered as new genotypes. This study also aimed at evaluating the population structure among the 65 non-redundant genotypes identified, which were grouped into two ancestral genetic groups. The mean probability of identity values of 0.072 and 0.510 (for the 6 SSR and 226 SNP sets, respectively) were determined. Minor differences were observed between frequencies of chlorotypes A and D within the non-redundant genotypes studied. Twenty-seven pedigrees were confirmed and nine new trios were established. Ancestors of eight genotypes remain unknown.

Winery residues generated by the wine industry represent an important sustainability challenge but also a valuable resource for producing vermicompost-derived products with potential agricultural applications through vermicomposting. This study evaluated the effects of aqueous vermicompost extracts produced from winery residues on the early in vitro development and physiological performance of garden cress (Lepidium sativum L.) and cucumber (Cucumis sativus L.) seedlings. Seedlings were cultivated on peat-based pellets (Jiffy-7^®) under controlled conditions and treated with two extract concentrations (10% and 20%, w/v) or distilled water (control). After 30 days, morphological traits (shoot height, leaf number and biomass) and biochemical parameters (photosynthetic pigments and total phenolics) were assessed. Both species showed high survival rates (>85%) and no phytotoxic symptoms. Compared with the control, VE20% increased chlorophyll a, chlorophyll b, and total chlorophyll contents in garden cress by 40.3%, 35.9%, and 38.9%, respectively, whereas VE10% increased chlorophyll a, total chlorophyll, and carotenoid contents in cucumber by 15.7%, 11.5%, and 25.0%, respectively. Total phenolic content did not differ significantly among treatments in either species (p > 0.05). These findings indicate that vermicompost extracts produced from winery residues exhibited low phytotoxic potential under the experimental conditions tested and influenced photosynthetic pigment accumulation without adversely affecting seedling growth. These responses warrant further investigation under ex vitro and field conditions to determine whether the observed physiological changes translate into relevant agronomic effects.