Copper stress in grapevine

Abstract

Copper-based fungicides are widely used mainly in organic viticulture, since the discovery of the Bordeaux mixture in the late 1800s. Copper sprays in vineyards can modify several aspects of grapevine physiology and metabolism by regulating the partitioning patterns of several mineral elements, including K, Ca and N, and the accumulation of sugars, nitrogen and lipids. The sequestration of Cu in the vacuole of grape cells constitutes a mechanism for toxic avoidance and several transporters belonging to the Ctr family may account for its distribution within the cell. The expression of VvCTrs in leaves and berries is modulated by the application of Bordeaux mixture throughout the fructification season. Moreover, Cu sprays also modify the microbiome of grape berry and soil. High Cu levels also affect the fermentation process indirectly by controlling the composition of the must and yeast communities and, directly, by compromising yeast growth and alcoholic fermentation kinetics, having great repercussions in the development of varietal and fermentative aromas in wine.