Exogenous phenylalanine application effects on phytochemicals, antioxidant activity, HPLC profiling, and PAL and CHS genes expression in table grapes (Vitis vinifera cv. ‘Qzl Ouzum’)

With the use of phenylalanine, the activity of the PAL and CHS enzyme and PAL and CHS gene expression were significantly increased and led to a greater accumulation of phenolic compounds and antioxidant activiety. This study suggests that the use of phenylalanine as a main precursor for the synthesis of phenolic compounds, can improve the phenolic composition of grapes and could be a practical approach to advance fruit quality in the production of grape cv. 'Qzl Ouzum'.