Cadmium tolerance mediated by GhBCAT12 through branched-chain amino acid degradation via vacuolar sequestration in cotton

Soil Cd 2+ pollution threatens agricultural safety. Branched-chain amino acid (BCAA) metabolism is involved in stress responses, but its role in cotton Cd 2+ tolerance remains unclear. Here, 16 GhBCAT genes were identified in Gossypium hirsutum , among which GhBCAT12 was significantly induced by Cd 2+ stress. Silencing GhBCAT12 increased Cd 2 + sensitivity, causing growth inhibition, oxidative damage, and cell death. Metabolomic analysis revealed the accumulation of leucine, isoleucine, and valine, with decreased acetyl-CoA, indicating that GhBCAT12 mediates BCAA degradation. This study reveals a novel pathway in which GhBCAT12 -mediated BCAA degradation provides acetyl-CoA precursors for the tricarboxylic acid (TCA) cycle, sustaining ATP production, which in turn powers vacuolar Cd 2 + sequestration. These findings provide a new target for improving heavy metal tolerance in crops.