Grafting the wine grape variety Cabernet Sauvignon onto salinity-tolerant rootstocks can improve salinity tolerance and grape yields in regions with high salinity soils. In this experiment, the effects of different rootstocks and rootstock combinations on the saline–alkaline stress (modified Hoagland nutrient solution + 50 mmol L⁻¹ (NaCl + NaHCO₃)) of Cabernet Sauvignon were studied. Correlation and principal component analyses were conducted on several physiological indicators of saline–alkaline stress. Salinity limited biomass accumulation, induced damage to the plant membrane, reduced the chlorophyll content and photosynthetic capacity of plants, and increased the content of malondialdehyde, sodium (Na⁺)/potassium (K⁺) ratio, and antioxidant enzyme activities (superoxide dismutase, peroxidase, and catalase). Significant differences in several indicators were observed among the experimental groups. The results indicate that the saline–alkaline tolerance of Cabernet Sauvignon after grafting was the same as that of the rootstock, indicating that the increased resistance of Cabernet Sauvignon grapes to saline–alkaline stress stems from the transferability of the saline–alkaline stress resistance of the rootstock to the scion.

In order to study the effect of exogenous 5-aminolevulinic acid (ALA) on the expression of genes associated with anthocyanin biosynthesis in the transcriptome of ‘Crimson Seedless’ grape (Vitis vinifera) peel, sequencing technology was used to compare the transcriptomes from water and ALA treated ‘Crimson Seedless’ grapes. Transcriptome sequencing was performed at two periods (d5 and d15) after peel treatment. The enrichment analysis of the Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathways indicated that the metabolic pathways induced by exposure to ALA were mainly the phenylpropanoid biosynthesis, flavonoid biosynthesis, anthocyanin biosynthesis, phenylalanine metabolism, and plant hormone signal transduction pathways. In the anthocyanin synthesis pathway, ALA treatment appeared to mainly regulate the phenylalanine ammonia-lyase, cinnamate 4-hydroxylase and chalcone synthase genes in the upstream pathway of anthocyanin synthesis, and the dihydroflavonol-4-reductase gene in the downstream pathway, with the effect being most obvious at d5.This study reveals the mechanism by which exogenous ALA promotes anthocyanin synthesis at the molecular level, and lays the foundation for further study of the physiological role of ALA.

In recent years, Colomerus vitis has caused serious economic losses due to reduced grape production in Xinjiang (northwest China). Several rootstock varieties have been reported to improve the resistance of Cabernet Sauvignon to Colomerus vitis. This study explored the influence of Cabernet Sauvignon with different rootstocks on the resistance to Colomerus vitis. In particular, Cabernet Sauvignon/Cabernet Sauvignon (CS/CS) was selected as the control, and Cabernet Sauvignon grafted with five resistant rootstocks (3309C, 1103P, 140R, SO4, and 5C) was employed as the treatment. The infestation rate and injury index of Colomerus vitis to grapevines was investigated, and insect-resistant types of grapevines with different rootstocks were determined. The resveratrol (Res) content, the gene expression of resveratrol synthase (RS), and the activities of peroxidase (POD), polyphenol oxidase (PPO), catalase (CAT), and superoxide dismutase (SOD) in the leaves of each rootstock grapevine were measured. The activity of the four enzymes and the content of Res were negatively correlated with the injury index. The results revealed the ability of the rootstock to improve the resistance of grapevines to Colomerus vitis by increasing the enzyme activity or Res content. In particular, 140R, SO4, and 5C rootstocks can be employed as rootstocks of the ‘Cabernet Sauvignon’ grapevine with resistance to Colomerus vitis. The contents of Res and the four resistance enzymes studied here can be used as indexes to evaluate the insect resistance of rootstock–scion combinations.

The types and contents of organic acids in wine grapes determine wine quality. To explore the effects of different rootstocks on the acid metabolism of ‘Cabernet Sauvignon’ grapes, various perennial rootstock–scion combinations were used as experimental materials. High-performance liquid chromatography (HPLC) was used to determine citric acid, tartaric acid, and malic acid contents during fruit development. Succinic acid and oxalic acid contents and the activity of related enzymes were measured using spectrophotometry. The expression levels of related genes were measured using a real-time fluorescence quantitative method. The results showed that all four rootstock types significantly reduced oxalic acid and citric acid contents in the grapes, while increasing succinic acid content to varying degrees. Employing 110R, SO4, and Kangzhen3 rootstocks increased tartaric acid and malic acid contents. Enzyme activity analysis revealed that 110R, SO4, and Kangzhen3 rootstocks increased the NAD-MDH enzyme activity, which positively correlated with malic acid content. Simultaneously, these rootstocks reduced the NADP-ME enzyme activity level. NAD-MDH and PEPC gene expression levels were higher in ‘Cabernet Sauvignon’ grapes grafted with 110R, SO4, and Kangan3 rootstocks compared to control self-rooted seedlings. Grafting these three rootstocks enhanced malic acid accumulation in ‘Cabernet Sauvignon’ grapes.