Ethylene is one crucial phytohormone modulating plants’ organ development and ripening process, especially in fruits, but its action modes and discrepancies in non-climacteric grape and climacteric peach in these processes remain elusive. This work is focused on the action mode divergences of ethylene during the modulation of the organ development and ripening process in climacteric/non-climacteric plants. We characterized the key enzyme genes in the ethylene synthesis pathway, VvACO1 and PpACO1, and uncovered that their sequence structures are highly conserved, although their promoters exhibit important divergences in the numbers and types of the cis-elements responsive to hormones, implying various responses to hormone signals. Subsequently, we found the two have similar expression modes in vegetative organ development but inverse patterns in reproductive ones, especially in fruits. Then, VvACO1 and PpACO1 were further validated in promoting fruit ripening functions through their transient over-expression/RNAi-expression in tomatoes, of which the former possesses a weaker role than the latter in the fruit ripening process. Our findings illuminated the divergence in the action patterns and function traits of the key VvACO1/PpACO1 genes in the tissue development of climacteric/non-climacteric plants, and they have implications for further gaining insight into the interaction mechanism of ethylene signaling during the modulation of the organ development and ripening process in climacteric/non-climacteric plants.

Exogenous gibberellin (GA) efficiently induces seeded grape parthenocarpy and improves berry quality, with VvGAMYB serving as a key response factor. However, the VvGAMYB-mediated regulatory networks underlying this process remain unclear. In this study, GA₃ treatment induced ovule abortion in ‘Wink’ grape, leading to the formation of parthenocarpic seedless berries. Exogenous GA drastically repressed VvGAMYB levels, thereby promoting parthenocarpy in grape ovaries. Through protein interaction screening, we identified 181 predicted VvGAMYB-associated proteins, which include differentially expressed genes related to hormone signaling, sugar metabolism, and transcriptional regulation, and further revealed that GA-induced grape parthenocarpy likely operates through a VvGAMYB-mediated network, coordinating key genes such as VvGID1B (GA signaling), VvRAP2-4 (ETH signaling), VvGAPC2 (glycolysis), and VvMETKs (methylation modification). Among these candidates, VvGAMYB repressed VvMETK2 promoter activity, whereas GA₃ treatment weakened this repression, as demonstrated by a dual-luciferase assay in tobacco. Collectively, this study established an integrative framework in which VvGAMYB orchestrates phytohormone crosstalk, sugar metabolism, and epigenetic modification during GA-induced parthenocarpy. Our findings provide significant insights into the molecular network of GA-induced grape parthenocarpy and offer key target genes for the molecular breeding of high-quality seedless grapes.