Could foliar applications of methyl jasmonate and methyl jasmonate + urea improve must grape aroma composition?

BACKGROUND: Grape aromas are formed by a great number of volatile compounds. Methyl jasmonate (MeJ) and urea (Ur) foliar applications have been studied to improve grape quality, but their combined application has never been studied. RESULTS: In both seasons, MeJ application enhanced terpenoids and C6 compounds synthesis, though decreased alcohols content. Moreover, MeJ + Ur treatment reduced benzenoids and alcohols and did not affect C-norisoprenoids content. However, there was no clear effect of these treatments on the rest of the volatile compounds. Multifactorial analysis showed a season effect on all volatile compounds, except terpenoids. Discriminant analysis showed a good separation among samples under treatment criterion. The great effect of MeJ treatment on terpenoids was probably due to this elicitor influencing their biosynthesis. CONCLUSION: Season has a strong influence on grapes aromatic composition since it affects all volatile compound families except terpenoids. MeJ foliar application enhanced terpenoids, C-norisoprenoids and C6 compounds synthesis, whereas decreased alcohols content; however, MeJ + Ur foliar treatment did not affect C-norisoprenoids and C6 compounds, and decreased benzenoids and alcohols grape compounds. Therefore, no synergistic effect was observed between Ur and MeJ on grape volatile compounds biosynthesis. Foliar application of MeJ seems to be sufficient to improve the aromatic quality of grapes. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.This work has been carried out thanks to funding from the Ministerio de Ciencia, Innovación y Universidades through the Project RTI2018-096549-B-I00. MG-L thanks the Universidad de La Rioja for her Margarita Salas contract funding by the Ministerio de Universidades and the European Union (Financed by the European Union-Next GenerationEU). SM-SR thanks Gobierno de La Rioja and RM-P thanks to INIA for their predoctoral contracts. EPP-Á thanks the Ministerio de Ciencia, Innovación y Universidades for her Juan de la Cierva-Incorporación contract