Work

Differential physiological responses of grafted cabernet sauvignon grapes to salt and saline–alkali stress: The dual role of VvGAD1 in GABA-mediated tolerance

Year: 2026

Type: article

Abstract: Saline–alkali stress induces substantially greater damage to grapevines than salt stress alone. How resistant rootstocks modulate the responses of the scion to these distinct types of stress has therefore become a central focus of research. however, the underlying molecular mechanisms for this differential tolerance remain poorly understood. Here, we compared self-grafted (CS/CS) and hetero-grafted (CS/1103P) Cabernet Sauvignon under salt and saline–alkali stress using morphophysiological and transcriptomic analyses. Saline–alkali stress led to more severe membrane lipid peroxidation, chloroplast ultrastructural damage, reactive oxygen species accumulation, and photosynthetic inhibition compared with salt stress alone. Rootstock 1103P markedly enhanced stress tolerance in grafted plants, as evidenced by lower H 2 O 2 and MDA levels, higher antioxidant enzyme activities, and scion-specific upregulation of VvGAD1 , which promoted γ-aminobutyric acid (GABA) accumulation. Functional validation assays showed that VvGAD1 overexpression increased callus antioxidant capacity, stabilized ion homeostasis, enhanced organic acid metabolism, and elevated the expression of stress-responsive genes under both salt and saline–alkali stress. Exogenous GABA further induced endogenous GABA biosynthesis and mitigated stress injury. Collectively, these results indicate that VvGAD1 primarily confers salt stress tolerance by maintaining ion balance and strengthening antioxidant defenses, while also contributing to organic acid metabolism and pH homeostasis under saline–alkali conditions. These findings have important implications for the breeding of stress-resistant grape cultivars.

Source: Industrial Crops and Products

DOI: 10.1016/j.indcrop.2026.122641