Low temperature is an important factor limiting plant growth. Most cultivars of Vitis vinifera L. are sensitive to low temperatures and are at risk of freezing injury or even plant death during winter. In this study, we analyzed the transcriptome of branches of dormant cv. Cabernet Sauvignon exposed to several low-temperature conditions to identify differentially expressed genes and determine their function based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG)enrichment analyses. Our results indicated that exposure to subzero low temperatures resulted in damage to plant cell membranes and extravasation of intracellular electrolytes, and that this damage increased with decreasing temperature or increasing duration. The number of differential genes increased as the duration of stress increased, but most of the common differentially expressed genes reached their highest expression at 6 h of stress, indicating that 6 h may be a turning point for vines to tolerate extreme low temperatures. Several pathways play key roles in the response of Cabernet Sauvignon to low-temperature injury, namely: (1) the role of calcium/calmodulin-mediated signaling; (2) carbohydrate metabolism, including the hydrolysis of cell wall pectin and cellulose, decomposition of sucrose, synthesis of raffinose, and inhibition of glycolytic processes; (3) the synthesis of unsaturated fatty acids and metabolism of linolenic acid; and (4) the synthesis of secondary metabolites, especially flavonoids. In addition, pathogenesis-related protein may also play a role in plant cold resistance, but the mechanism is not yet clear. This study reveals possible pathways for the freezing response and leads to new insights into the molecular basis of the tolerance to low temperature in grapevine.

Downy mildew is a major disease that severely restricts the healthy and sustainable development of the global grape and wine industry, so there is significant interest in breeding high-quality disease-resistant varieties. In this study, hybridization was carried out between two disease-resistant and four high-quality varieties for eight hybrid combinations. The downy mildew resistance of 6 hybrid parents and 350 hybrid F₁ progeny was determined by the leaf disc inoculation test, and the frequency distribution of the disease resistance grades was analyzed for the different populations. Agarose gel electrophoresis and disease resistance identification were used to screen SSR molecular markers of the tested hybrids for resistance to downy mildew. The results showed that minor disease-resistance genes in V. vinifera varieties were the main determinant of the variation in disease susceptibility among different varieties. V. vinifera resistance to downy mildew is inherited by a quantitative trait controlled by multiple genes. Intraspecific hybridization of V. vinifera can be applied to breed suitable intermediate materials or new types of disease resistance. The screening and verification of simple-sequence repeats (SSR) as molecular markers revealed that UDV-304, UDV-305, and UDV-737 could be used as standard markers for the identification of downy mildew resistance of hybrid progeny of Ecolly and Cabernet Sauvignon, UDV-305 could be used for the hybrid progeny of Meili and Cabernet Sauvignon, and VMC8g9 could be used for the hybrid progeny of Ecolly or Meili and Dunkelfelder. The disease-resistant progeny selected in this study can be used as intermediate materials for the breeding of new high-quality, disease-resistant varieties by intraspecific recurrent selection in V. vinifera. The screened standard markers can be utilized for rapid batch identification of hybrid progeny of different hybrid combinations to facilitate molecular marker-assisted breeding.

Biodegradable liquid film (BLF) improves soil structure and increases plant freezing tolerance after spraying on the surface of soil and plant. In this study, the effects of BLF on grape composition and volatile compounds in Cabernet sauvignon (Vitis vinifera L.) grapes were determined by spraying BLF during the dormant periods over three years. The aim of the study was to evaluate the potential impact of BLF as an overwintering protection measure on grape fruit quality. In 2020 and 2021, BLF spraying increased reducing sugar content and 100-berry weight, decreased titratable acid content, and improved the maturity factor. Compared with the vines not sprayed with BLF, the content of total phenols and total anthocyanins in grape skins showed an increase over the three-year period, with the largest increases of 31.92% and 48.38%, respectively, and the content of total tannins and total flavan-3-ols increased in 2020 and 2021. BLF treatment also increased the total phenolic content in seeds for all three years, reaching a significant level in 2019, 16.38% higher than control treatment (CK). HPLC analysis showed that BLF treatment affected the content and composition of monomeric anthocyanins in grape skins, especially in 2021, BLF treatment significantly increased the content of nine monomeric anthocyanins, and the proportion of acetylated and coumaroylated anthocyanins. However, GC-MS analysis indicated that BLF had little effect on volatile compounds. These results suggest that BLF can be used as an overwintering protection measure in cold regions to promote the accumulation of sugars and polyphenolics, thereby improving overall grape quality.

Downy mildew caused by Plasmopara viticola is an important disease in grape production, particularly in the highly susceptible, widely cultivated Vitis vinifera L. Breeding for disease resistance is an effective solution, and V. vinifera intraspecific crosses can yield progeny with both disease resistance and high quality. To assess the potential of intraspecific recurrent selection in V. vinifera (IRSV) in improving grapevine resistance to downy mildew and to analyze the pattern of disease resistance inheritance, the disease-resistant variety Ecolly was selected as one of the parents and crossed with Cabernet Sauvignon, Marselan, and Dunkelfelder, respectively, creating three reciprocal combinations, resulting in 1657 hybrid F1 progenies. The primary results are as follows: (1) significant differences in disease resistance among grape varieties and, significant differences in disease resistance between different vintages of the same variety were found; (2) the leaf downy mildew resistance levels of F1 progeny of different hybrid combinations conformed to a skewed normal distribution and showed some maternal dominance; (3) the degree of leaf bulbous elevation was negatively correlated with the level of leaf downy mildew resistance, and the correlation coefficient with the level of field resistance was higher; (4) five progenies with higher levels of both field and in vitro disease resistance were obtained. Intraspecific hybridization can improve the disease resistance of offspring through super-parent genetic effects, and Ecolly can be used as breeding material for recurrent hybridization to obtain highly resistant varieties.

Cold resistance is an important characteristic of sustainable development in the grape industry. The intraspecific recurrent selection in the Vitis vinifera (V. vinifera) method uses high-quality varieties as breeding materials and the substitution and accumulation of minor resistance genes, breeding high-quality grapes with cold resistance. This study was conducted to identify and genetically analyse the cold resistance of a V. vinifera hybrid population (Ecolly × Dunkelfelder), screen for highly resistant and sensitive plant samples, and use high-throughput sequencing to perform transcriptome sequencing and related differential gene expression analysis on each sample. The results revealed that the cold resistance of the hybrid offspring population was characterised by continuous quantitative trait inheritance, with 38 differentially expressed genes (7 upregulated genes and 31 downregulated genes) between the high resistance and high-sensitivity types. Analysis of genes related to various pathways, related to cold resistance, revealed that CYP76F10, Dxs, GERD, NMT, GDE1, glgC, and DHQ-SDH, as well as transcription factor MYB, HB, and MADS family genes, are key candidate genes for V. vinifera cold resistance research. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) was used to investigate the expression characteristics of the six genes that were differentially expressed genes, the results of which were essentially consistent with the results of RNA-seq. Specifically, NMT may enhance cold resistance by enhancing membrane lipid stability. The synergistic expression pattern of CYP76F14 and Dxs suggests its key role in terpene synthesis. By exploring potential genes related to micro effects, a theoretical foundation for further exploration of new high-quality cold-resistant grape varieties has been provided.

Soil mulching influences soil organic carbon (SOC) dynamics and microbial communities, yet the functional potential linking these factors remains unclear. This two-year field study compared biodegradable liquid film (BLF, C:N = 26:1, 161 kg C·ha⁻¹) and grapevine branch mulch (GBM, C:N = 51:1, 2790 kg C·ha⁻¹) applied in-row in a vineyard, with clean tillage as control. The Vitis vinifera cv. Meili was used as the test material, SOC fractions were determined and metagenomic sequencing was performed. The results showed that GBM had the highest SOC content and significantly increased the levels of total organic carbon, all five labile fractions, and the three recalcitrant fractions. BLF significantly increased the levels of recalcitrant fractions, while its effect on labile fractions varied by year. Metagenomic analysis revealed that the two mulching treatments significantly influenced the abundances of Acidobacteria, Verrucomicrobia, and Bacteroidetes. Redundancy analysis identified soil moisture, pH, SOC, and total nitrogen as key drivers of community structure. Mulching downregulated carbon fixation and methane metabolism genes but upregulated carbohydrate metabolism pathways, including O-glycan biosynthesis, which correlated positively with SOC. Glycosyl transferases were the dominant carbohydrate-active enzymes across all treatments. These results demonstrate that GBM and BLF differentially affect SOC fractions and microbial functional traits, providing empirical evidence for mulch selection in vineyard carbon management.