Effects of combined application of abscisic acid and methyl jasmonate on the regulation of anthocyanin and monoterpene biosynthesis in ‘Jumeigui’ grape

Although both abscisic acid (ABA) and methyl jasmonate (MeJA) play significant roles in regulating the development and quality of grape ( Vitis vinifera L.) berries, the regulatory effects and mechanisms of the combined application of ABA and MeJA remain unclear. To further explore the optimal combination of these hormones for regulating the development of grape quality, combined ABA and MeJA treatments were carried out in this study, with 'Jumeigui' grape used as the material. The results indicated that the combined treatment of high-ABA and low-MeJA (HA+LM) increased the sugar-acid ratio, promoted the accumulation of phenolic substances in grape skins, and resulted in anthocyanin content 168.9% higher than that of the control, significantly enhancing coloration. Additionally, the combined treatment of low-ABA and low-MeJA (LA+LM) was more conducive to the accumulation of phenols in grape, especially phenolic acid and resveratrol, as the total phenolic content increased by 38.96% relative to that of the control. Moreover, the expressions of aroma-related genes were upregulated by the combined high-MeJA treatments. The combined treatment of high-ABA and high-MeJA (HA+HM) markedly increased terpene biosynthesis, followed by the LA+HM treatment, increasing the intensity of the rose flavor characteristics of the 'Jumeigui' grape. Therefore, the combination of MeJA and ABA at different concentrations had distinct effects on fruit quality and appropriate combinations can be selected according to the specific needs for the targeted metabolites.