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.

Terpenoids are vital secondary metabolites in plants that function as agents for defense and stress resistance. These genes not only play crucial roles in plant growth and development but also function in diverse biological group interactions. Terpenoids released by fruit trees possess defensive properties and constitute a class of aromatic compounds. For some fruits, terpenoids are indispensable indicators for evaluating fruit quality and the economic value. Significant research progress has been made in terpenoids biosynthesis and regulation. In this review, we introduce the main terpenoids of fruit trees, emphasize synthetic enzymes and regulatory factors involved in the mevalonate pathway and the methylerythritol pathway, and analyze TPS gene family identification and diversity in several fruit tree species. Moreover, the regulation of terpenes biosynthesis, including the molecular interaction mechanisms of environmental factors and hormone signaling pathways, are comprehensively described. Our objective is to summarize the molecular regulatory network and research foundation of terpenoids biosynthesis, providing a reference for investigations of metabolic pathways and promoting the development of techniques for the regulation and breeding of terpenoids in fruit trees.

Evaluating plant stress tolerance and screening key regulatory genes under the combined stresses of high temperature and drought are important for studying plant stress tolerance mechanisms. In this study, the drought tolerance of five grape varieties was evaluated under high-temperature conditions to screen key genes for further exploration of resistance mechanisms. By comparing and analysing the morphological characteristics and physiological indicators associated with the response of grapevines to drought stress and integrating them with the membership function to assess the strength of their drought tolerance, the order of drought tolerance was found to be as follows: 420A>110R>Cabernet Sauvignon (CS)>Fercal>188-08. To further analyse the mechanism of differences in drought tolerance, transcriptomic sequencing was performed on the drought-tolerant cultivar 420A, the drought-sensitive cultivar 188-08 and the control cultivar CS. The functional analysis of differential metabolic pathways indicated that the differentially expressed genes were enriched mainly in biological process category, that 420A had higher antioxidant activity. Furthermore, differentially expressed transcription factors were analyzed in five grape varieties. Genes like VvAGL15, VvLBD41, and VvMYB86 showed close associations with drought tolerance, indicating their potential role in regulating drought tolerance and research significance.