VvABCC3 enhances aluminum tolerance in grapevine by promoting acetate synthesis and secretion while reducing ROS...

Aluminum (Al) toxicity severely inhibits plant growth and development, particularly in acidic soils. Plants employ external and internal detoxification to counteract Al toxicity; however, the underlying mechanisms remain poorly understood. Our study revealed a significant alteration in the transcriptomic profile of grape roots under AlCl₃ stress, including a strong induction of VvABCC3 expression. Functional analyses revealed that VvABCC3 overexpression enhanced Al tolerance in grape roots, calli, and Arabidopsis seedlings, whereas CRISPR/Cas9-mediated knockout of VvABCC3 increased Al sensitivity, as indicated by severe phenotypic defects, reduced growth, and elevated malondialdehyde (MDA) levels in grape calli. Mechanistically, VvABCC3 overexpression promoted acetate synthesis and secretion, leading to reduced Al accumulation in roots under Al stress. This process was associated with elevated plasma membrane H⁺-ATPase (PMA) activity and upregulated expression of PMA5.2, PMA6, and PMA10, suggesting enhanced energy provision for acetate efflux. Additionally, VvABCC3 overexpression boosted the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), thereby reducing reactive oxygen species (ROS) accumulation in grape roots and Arabidopsis leaves. Our findings demonstrate that VvABCC3 enhances Al tolerance by stimulating acetate synthesis and secretion, reducing root Al accumulation, enhancing antioxidant capacity, and mitigating ROS-induced oxidative damage. This study provides new insights into the molecular mechanisms of Al detoxification in plants.