Flavonoid and amino acid profiling on Vitis vinifera L. cv Tempranillo subjected to deficit irrigation under elevated temperatures

Throughout the southern Mediterranean regions of Europe, projected climate warming combined with severe droughts during the growing season may alter grape metabolism, thus modifying the nutritional value of berries and the quality of wines. This study investigated the effects of pre- and post-veraison drought under elevated temperatures on berry skin metabolism of two Tempranillo clones (CL).Experimental assays were performed on fruit-bearing cuttings from CL-1089 and CL-843 of Vitis vinifera (L.) cv. Tempranillo subjected to two temperature regimes (24/14 °C or 28/18 °C (day/night)) combined with three irrigation regimes during berry ripening: (i) water deficit from fruit set to veraison (early deficit, ED); (ii) water deficit from veraison to maturity (late deficit, LD); and (iii) full irrigation (FI). At 24/14 °C, the LD treatment performed better than the ED treatment. Differences were attenuated at 28/18 °C and responses were modulated by type of clone. Elevated temperatures induced the accumulation of hexoses and amino acids in berries. ED at 24/14 °C reduced anthocyanins and flavonols, which may decrease the antioxidant properties of fruits. In contrast, the levels of these secondary metabolites did not decrease when LD was applied. Our results suggest that the adaptation of grapevines for climate change might be plausible with the optimization of timing of water deficit and the appropriate selection of clones