The β-1,3-glucanase gene is widely involved in plant development and stress defense. However, an identification and expression analysis of the grape β-1,3-glucanase gene (VviBG) family had not been conducted prior to this study. Here, 42 VviBGs were identified in grapevine, all of which contain a GH-17 domain and a variable C-terminal domain. VviBGs were divided into three clades α, β and γ, and six subgroups A–F, with relatively conserved motifs/domains and intron/exon structures within each subgroup. The VviBG gene family contained four tandem repeat gene clusters. There were intra-species synteny relationships between two pairs of VviBGs and inter-species synteny relationships between 20 pairs of VviBGs and AtBGs. The VviBG promoter contained many cis-acting elements related to stress and hormone responses. Tissue-specific analysis showed that VviBGs exhibited distinct spatial and temporal expression patterns. Transcriptome analysis indicated that many VviBGs were induced by wounds, UV, downy mildew, cold, salt and drought, especially eight VviBGs in subgroup A of the γ clade. RT-qPCR analysis showed that these eight VviBGs were induced under abiotic stress (except for VviBG41 under cold stress), and most of them were induced at higher expression levels by PEG6000 and NaCl than under cold treatment. The chromosome localization, synteny and phylogenetic analysis of the VviBG members were first conducted. The cis-acting elements, transcriptome data and RT-qPCR analysis showed that VviBG genes play a crucial role in grape growth and stress (hormone, biotic and abiotic) responses. Our study laid a foundation for understanding their functions in grape resistance to different stresses.

Vitis vinifera is a fruit tree species of great economic value worldwide. Nevertheless, chilling injury induced by cold stress restricts its yield and hinders the development of the grape industry. Based on previous findings of our research group that exogenous trehalose enhances abiotic stress tolerance in grape callus, this study adopted physiological, transcriptomic and metabolomic approaches to explore the potential regulatory relationships associated with exogenous trehalose. In this study, trehalose treatment alleviated chilling injury under 12 °C cold stress and increased the fresh weight of Vitis vinifera 'Thompson Seedless' callus. Meanwhile, trehalose application significantly elevated endogenous trehalose and soluble sugar content in grape callus, accompanied by increased activities of POD, SOD, and CAT, as well as reduced levels of MDA and O₂•⁻. KEGG enrichment analysis of transcriptomic data revealed that DEGs were mainly enriched in pathways related to biosynthesis of secondary metabolites, plant hormone signal transduction, starch and sucrose metabolism, and the MAPK signaling pathway in plants. Key DEGs included BAMS, STS, IAA, RLKs, and BGLU, while differentially expressed transcription factors were predominantly distributed in the AP2/ERF-ERF and MYB families. WGCNA identified the brown and turquoise modules as modules putatively correlated with physiological traits in grape callus, from which candidate genes potentially involved in trehalose-mediated cold response, including VQ22, RGLG2, PPR21, CML16, and SPL6, were screened. Combined transcriptomic and metabolomic analysis showed that DEGs and DAMs were jointly notably altered in the metabolic pathways of flavonoids, benzenes and their substituted derivatives, alkanolamines, terpenoids, and alkaloids. Moreover, all DAM-interacting genes identified were DEGs from the transcriptome. RT-qPCR analysis confirmed that the expression patterns of the selected cold-responsive genes were reliable and consistent with the transcriptomic results. Using integrated physiological, transcriptomic and metabolomic approaches, we identified candidate modules and genes related to cold tolerance in grape callus, as well as physiological responses and potential pathways underlying trehalose-mediated cold tolerance. We also characterized candidate genes involved in this regulatory process, providing a theoretical reference for exploring cold tolerance mechanisms in grape callus.

Low temperatures severely restrict plant growth and agricultural productivity, and exploring cold tolerance mechanisms is critical. This study investigated the combined effects of grape-derived transcription factor gene VyMYB24 and the synthetic cytokinin CPPU on cold tolerance in transgenic tobacco. Under low-temperature stress, tobacco plants overexpressing VyMYB24 and treated with CPPU exhibited significantly alleviated wilting, higher chlorophyll contents, and an improved net photosynthetic rate compared to controls. These plants also showed a lower relative conductivity and malondialdehyde (MDA) content, higher proline accumulation, and elevated activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), accompanied by reduced reactive oxygen species (ROS), hydrogen peroxide (H₂O₂), and superoxide anions (O₂$\stackrel{\mathrm{-}}{·}$). The results confirm that VyMYB24 and CPPU synergistically improve cold tolerance via membrane stabilization, enhanced antioxidant defense, and maintained photosynthetic capacity, providing a theoretical foundation for the rational application of CPPU in the cultivation and management of grapes under low-temperature conditions.

Trehalose is widely involved in the processes of plant development and in defense against stress. To date, the role of the trehalose-6-phosphate phosphatase (TPP) genes in grapevine subjected to abiotic stress remains unreported. Here, seven VvTPPs were identified in grape (Vitis vinifera), all of which contained the TPP domain. Synteny analysis revealed two gene pairs with grape and four gene pairs between grape and Arabidopsis. Phylogenetic analysis showed that VvTPPs were distributed in Class Ⅰ, Class ⅡⅠ, and Class IV. The VvTPP proteins were highly conserved in both their distribution pattern and the number of conserved motifs. The VvTPPs contained a large number of introns and exons. The VvTPP promoter sequences contained numerous cis-acting elements associated with stress and hormonal responses. Tissue-specific analysis revealed that VvTPPA was highly expressed in all grape tissues. RT-qPCR analysis indicated that seven VvTPPs were induced by at least one of the cold, drought, and salt stresses. Finally, VvTPPA overexpression enhanced salt tolerance in grape callus and Arabidopsis thaliana. Based on expression and functional analyses of VvTPPs in grape, the role of VvTPPA in salt stress response was elucidated, identifying it as a key gene for raising stress resistant grape plants in future through breeding programs.