Jasmonates signalling plays a key role in modulating berry terpenes accumulation under water deficit conditions in Vitis vinifera L. (cv. Sangiovese)

Terpenes are among the most important aroma compounds synthesized in grape berries and vine water status affects their accumulation. Although previous studies showed that exogenous hormones applications significantly affected terpenes accumulation, the signalling network involved in regulating their biosynthesis under drought conditions is still unclear. This experiment imposed several deficit irrigation treatments, to elucidate the role of the endogenous hormones signalling network in regulating berry terpenes biosynthesis under water deficit conditions. Berry monoterpenes increased when water deficit was applied during the green or the lag-phase of berry development. Berry abscisic acid and jasmonic acid concentrations were significantly increased by water deficit, regardless of when it was imposed, whereas salicylic acid showed significant differences between irrigation treatments only at veraison. Under water deficit conditions, correlation analyses suggested that jasmonates may be key hormones regulating the biosynthesis of berry monoterpenes, especially in the glycosylated form. Vines subjected to water deficit before veraison showed increased jasmonic acid and methyl jasmonate levels in berries, with the highest monoterpene concentrations measured in the same berries at harvest. These results suggested that endogenous jasmonates may play a key role in water deficit induced signalling that regulates berry monoterpenes biosynthesis.