Transcriptome analysis reveals the enhancing effects of gamma‐aminobutyric acid on the tolerance of grapevines to cadmium stress by reducing cadmium accumulation

Grape (Vitis vinifera) is one of the most widely cultivated fruit crops in the world, known for its juicy and delicious berries. However, Cd contamination of vineyard soils poses a significant threat to the safe production of grapes. Gamma-aminobutyric acid (GABA) can reduce cadmium (Cd) uptake in crops, but its mechanism of action remains unclear. In this study, the molecular mechanism by which GABA affects Cd uptake in grapevines under Cd stress was investigated by the transcriptome analysis. GABA promoted grapevine growth by increasing the biomass under Cd stress. It also reduced the Cd content in grapevines and decreased Cd accumulation in subcellular fractions, including the cell wall, organelles and membranes and soluble fractions. Compared with Cd treatment, GABA reduced Cd contents in roots and shoots by 13.59% and 14.81%, respectively. Transcriptome analysis showed that GABA regulates Cd transport by downregulating the expression of genes related to Cd absorption (VvHMA1 and VvNramp3) and upregulating the expression of efflux genes (VvABCG5 and VvABCG9). Additionally, GABA upregulated the expression of antioxidant enzyme-related genes (VvGST1, VvGST2, VvPOX2 and VvPOX1), thereby alleviating oxidative damage under Cd stress. This study reveals that GABA enhances grapevine tolerance to Cd stress by regulating the expression of genes involved in Cd transport and detoxification, as well as enhancing antioxidant capacity.