Application of ABA and GA3 modulate synthesis of polyphenols, terpenes and free amino acids in Vitis Vinifera L.

Abstract

ABA and gibberellins are terpenic phytohormones that modulate several physiological responses. In many species the resistance to stress conditions is related with increases of secondary metabolites, including polyphenols and terpenes (particularly ABA), and the amino acid proline. This study investigated polyphenol, terpene and amino acid profiles in grape plants submitted to ABA and GA3 application. By GC–EIMS analysis of berry, leaf and roots 19 terpenes, including monoterpenes, sesquiterpenes, diterpenes and triterpenes were characterized. Also, 14 amino acids were identified, with L-Glutamic acid and L-Aspartic acid, both related with antioxidant defense, as the most abundant in leaf tissues. By HPLC-MWD the anthocyanin polyphenol profile was assessed. Applications of the two phytohormones decreased the free amino acid levels, presumably used as precursors of secondary metabolites; especially triterpenes involved in acclimation to stress that were augmented. However, L-Glutamic acid and L-Aspartic acid were specifically enhanced after hormonal treatment. ABA applications improved synthesis of polyphenols with antioxidant properties suggesting mechanisms of defense against oxidative damage. Also, L-Proline accumulated whereas L-Phenylalanine was decreased, in concordance with literature showing an osmotic adjustment in water deficit-stressed plants.