Bouquet is a captivating wine characteristic that affects consumer consumption. Wine lactone correlates with both precursor ((E)-8-carboxylinalool) concentration and wine age that has the greatest contribution to bouquet. In wine grape, cytochrome P450 VvCYP76F14 can catalyze trisubstrate-triproduct reaction processes (hydroxylation, dehydrogenation and carboxylation) to produce (E)-8-carboxylinalool. However, the exact mechanism of the whole reaction is unclear. Here, we unraveled the multi-catalysis mechanism with the aim of rapid conversion of linalool into (E)-8-carboxylinalool in winemaking. Results showed that the redox partner NADPH cytochrome P450 reductase (VvCPR1) was indispensable for hydroxylation and carboxylation, but not dehydrogenation oxidation. Furthermore, the VvCYP76F14-VvCPR1 complex was introduced in the aging stage of winemaking and results showed that the complex could improve the bouquet by increasing the content of wine lactone and shortening the aging time. Nonetheless, this study reveals the trisubstrate-triproduct reaction mechanism of VvCYP76F14 and the VvCYP76F14/VvCPR1 complex has the potential use for wine bouquet enrichment.

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.

In plants, Ferritin is the earliest discovered regulator of iron (Fe) metabolism and plays a critical role in maintaining Fe storage and sequestration, which contributes to cellular Fe homeostasis and tolerance to abiotic stresses. However, biological functions of Ferritin proteins in perennial fruit crops are largely rare. In this study, VvFerritin1 was isolated from ‘Irsay Oliver’ table grape, and it was mainly expressed in roots and induced under Fe toxicity, H₂O₂ stress, and abscisic acid (ABA) treatment. Complementation of VvFerritin2 in yeast mutant DEY1453 directly restored the mutant growth, and VvFerritin1 can transport Fe²⁺ in yeast. The heterologous expression of VvFerritin1 in fer1-2 mutant effectively rescued the dwarfed growth of Arabidopsis fer1-2 mutant, under the control condition, Fe toxicity, or H₂O₂ stress, embodied in enhanced fresh weight (126%, 81%, or 48%), total root length (140%, 98%, or 64%), total root surface (70%, 84%, or 120%), and total leaf chlorophyll (56%, 51%, or 53%), respectively. In particular, tissue Fe concentration and activities of nitrite reductase (NiR), aconitase (ACO), and succinate dehydrogenase (SDH) were significantly enhanced in fer1-2/35S::Ferritin1 lines, respectively, compared to that of fer1-2 mutant. This work contributes to the study of molecular mechanisms of Fe storage and homeostasis in ‘Irsay Oliver’ table grape.

The seedless trait in grapes primarily arises from pseudo-parthenocarpy, driven by early seed abortion involving programmed cell death (PCD) and autophagy. However, the specific regulatory networks governing these pathways remain poorly defined. To address this, we systematically characterized the PCD-related (vacuolar processing enzyme [VPE] and metacaspase [MC]) and autophagy-related (ATG) gene families in the seedless cultivar ‘Jingkejing’ utilizing comprehensive bioinformatic analyses, spatiotemporal transcriptomic profiling, and transient expression assays. We identified three VPE, six MC, and 33 ATG genes, whose promoters were significantly enriched in hormone-responsive and transcription factor (TF)-binding motifs. Transcriptomic profiling across critical seed abortion stages highlighted VvγVPE and VvMC9 as key differentially expressed genes. Furthermore, protein–protein interaction predictions indicated extensive crosstalk among PCD/ATG proteins, kinases, and ubiquitin system components. Notably, transient expression assays confirmed that two core transcription factors, VvWRKY46 and VvERF71, specifically regulate downstream PCD-related targets, supporting a proposed multi-hormonal and TF-mediated regulatory network during seed abortion. These findings elucidate the molecular mechanisms underlying pseudo-parthenocarpy, providing essential candidate gene resources for the marker-assisted breeding of seedless grapes.