Summary: Grapes, as one of the world's oldest economic crops, are severely affected by grape powdery mildew, causing significant economic losses. As a phytoalexin against powdery mildew, stilbenes and their key synthetic gene, stilbene synthase (STS), are highly sought after by researchers. In our previous research, a new gene, VqNSTS2, was identified from Vitis quinquangularis accession 'Danfeng‐2' through transcriptomic analysis. However, the function and molecular mechanism of VqNSTS2 gene remain unknown. Here, by characterization and transient overexpression of VqNSTS2, we demonstrated that its expression product, stilbenes, can be detected in the model plant tobacco, which does not inherently contain STSs. After artificially inoculating transgenic Arabidopsis lines overexpressing VqNSTS2 with Golovinomyces cichoracearum, it was found that VqNSTS2 actively moved to the pathogen's haustorium after responding to the pathogen, recognized and enveloped the haustorium, blocking the pathogen's infection and invasion and exhibited disease resistance. Furthermore, Agrobacterium‐mediated stable overexpression of VqNSTS2 promoted stilbene accumulation and enhanced resistance of the V. vinifera susceptible cultivar 'Thompson Seedless' to E. necator. Additionally, through screening and identification, a transcription factor, VqERF062, was found to directly bind to the DRE and RAA motifs on ProVqNSTS2, positively regulating VqNSTS2 expression. Moreover, VqERF062 directly interacted with VqERF1B to promote the transcription of VqNSTS2 in addition to forming a homodimer with itself. Taken together, our findings reveal that the VqERF1B‐VqERF062‐ module is required for grape resistance to E. necator and providing insights into the regulatory mechanism of stilbenes biosynthesis. [Correction added on 22 March 2025, after first online publication: The 7th sentence in summary is updated in this version.].

Seedlessness in grapes is much appreciated by consumers and especially in cultivars consumed either as table grapes or as raisins. In many parts of the world, low temperature is the main environmental stress limiting grape production. In this study, stenospermocarpic (seed abortion) cultivars were selected as the female parents while seeded cold-resistant cultivars were selected as the male parents to develop new cold-resistant seedless grapes using embryo rescue technology, which has previously been shown to be a highly efficient way of breeding seedless grapes. Here, we report optima in genotype, sampling time, and culture medium for the embryo rescue of 14 hybrid combinations. Our results indicate that the embryo development rate (39.9%) and the seedlings rate (21.5%) were highest among the 14 crosses when ‘Ruby Seedless’ was used as the female parent and ‘Beibinghong’ was used as the male parent. The best sampling times for ‘Yuehong Wuhe’, ‘Ruby Seedless’, and ‘Melissa seedless’ were 37, 55, and 52 days after flowering, respectively. Embryo rescue efficiency was highest when the sucrose concentration for seedlings was maintained at about 1.0%. Using molecular markers, we detected 91 hybrids with seedless traits and 18 hybrids with cold resistance traits.

Grapevine leafroll-associated virus (GLRaV) is a globally widespread disease that causes substantial economic losses in the wine industry. In severely affected vineyards, GLRaV can reduce grape yield by 20–40%. This study aimed to evaluate the effects of GLRaV infection on polyphenolic and volatile organic compound contents, as well as on the sensory profiles of the resulting wines. A comparative analysis was conducted between GLRaV-3-infected and healthy Cabernet Sauvignon grapes and their corresponding wines. Results show GLRaV-3 significantly alters grape and wine quality. In infected grapes, sugar content decreased while titratable acidity increased. Polyphenol composition was notably altered: phenolic acids and flavonols increased by 22.46% and 15.27%, respectively, whereas flavanols decreased by 17.86%. The levels of aldehydes and C₆ compounds also rose significantly in the berries. Wines produced from infected grapes showed lower alcohol content and reduced dry extract. Phenolic acids and flavanols were decreased, but total flavonols increased by 12.54%. Among volatile compounds, alcohols, phenols, and fatty acids were elevated, while esters declined by 13.36%. These chemical changes directly influenced sensory attributes. Compared with wines from healthy grapes, those from infected grapes exhibited improved tannin texture and longer aftertaste. However, they were inferior in color intensity, aroma intensity, body fullness, and varietal typicity.

Grapes are widely cultivated around the world and valued for their rich nutritional content and versatile use in various industries. However, grape powdery mildew (PM) threatens grape production. This study aimed to identify and characterize PM resistance genes in Chinese wild grapevine (Vitis quinquangularis). Grape PM resistance is associated with stilbene synthases (STSs). Here, we isolated VqNSTS6 from the Chinese wild grapevine accession ‘Danfeng-2’ that exhibits high PM resistance. Overexpression of VqNSTS6 in the susceptible ‘Thompson Seedless’ variety induced PM resistance, whereas its transient knockdown in ‘Danfeng-2’ diminished this resistance. Furthermore, VqNSTS6 expression was upregulated by VqGT3, resulting in stilbene accumulation and enhanced PM resistance. However, stilbene overaccumulation induced Mitogen-Activated Protein Kinase 4 (MAPK4) phosphorylation, which in turn triggered VqGT3 phosphorylation and degradation, consequently downregulating VqNSTS6 and mitigating excessive stilbene accumulation. Additionally, VqNSTS6-GFP moved toward and wrapped around pathogen haustoria, forming a barrier preventing Golovinomyces cichoracearum invasion of Arabidopsis (Arabidopsis thaliana). The characterization of the STS gene VqNSTS6 conferring PM resistance opens avenues for breeding PM-resistant grapevine genotypes.