Induction of polyphenols in seedlings of Vitis vinifera cv. Monastrell by the application of elicitors

Leaf removal in the fruit-zone has been employed to improve cluster light exposure and ventilation and therefore increase metabolite accumulation and reduce botrytis incidence in berries. When applied before flowering (early defoliation – ED), it can also decrease cluster compactness and regulate yield in high-yielding varieties. This study aimed to evaluate the impact of ED on the physiology and metabolism of Aragonez (syn. Tempranillo) berries along the ripening period. The experiment was set up in 2013 at a commercial vineyard located in the Lisbon winegrowing region.

The first vineyards in Northern Europe were in Denmark in the 15th century, in the southern parts of Sweden and Finland in the 18th century at 55–60 degrees latitude. The grapes grown there have not been made into wine, but the grapes have been eaten at festive tables. The resurgence of viticulture has started with global warming, and currently the total area of viticulture in the Nordic countries, including Norway, is estimated to be 400–500 hectares, most of which is in Denmark. Southern Finland, like all southern parts of Northern Europe, belongs to the cool-cold winegrowing area.

Red grape pomace can be an important source of polysaccharides, but currently they are little studied and even less with viable and environmental extraction processes (green extraction). These green techniques must be able to break the cell wall so that the compounds contained in the cells, including polysaccharides, are released and can have a great influence on extraction yields, the chemical structure of polysaccharides and applications in wines. Amongst the emerging green techniques most applied to the extraction of bioactive compounds, such as polysaccharides, high-power ultrasound (US) and enzyme-assisted extraction stand out.

Grape composition is strongly influenced by climate conditions. Their expected modifications in near future, notably because of increased temperatures, could significantly modify the biochemical composition of berries at harvest, and thus wine typicity and quality. Elevated temperatures favor sugar accumulation in grapes, enhance malic acid degradation and modify the amino acid content. They also reduce significantly anthocyanin accumulation in Merlot, leading to the imbalance between anthocyanins and sugars, while no significant effects on final anthocyanin levels were reported in Tempranillo[1] and finally affect aromas or aroma precursors.

Trichoderma is one of the most widely used fungal biocontrol agents on vineyards due to its multiple benefits on this crop, such as its fungicidal and growth promoting capacity. In this work, we have analyzed the effect on the concentration of nutrients in grapevine leaves and on the quality of the grape must after spraying an autochthonous strain of Trichoderma harzianum and one of the main secondary metabolites produced by this genus, 6-pentyl-α-pyrone (6PP).