GhPDC2, a TPP-required cofactor gene contributes to flooding tolerance in cotton (Gossypium hirsutum L.)

ABSTRACT Cotton is susceptible to waterlogging stress. Under hypoxic conditions, cellular energy production declined, shifting pyruvate metabolism from aerobic respiration to anaerobic fermentation. In this pathway, Pyruvate decarboxylase 2 ( PDC2 ) catalyzes the conversion of pyruvate to acetaldehyde and subsequently ethanol, activating glycolysis to sustain ATP production, which is crucial for basal respiration and stress tolerance. However, the functional role of PDC2 in mediating cotton’s tolerance response to waterlogging stress remains largely unexplored. In this study, we present preliminary evidence that GhPDC2 functions as a positive regulator of waterlogging tolerance in cotton. Transcriptomic profiling revealed significant upregulation of GhPDC2 in roots subjected to waterlogging, implying its involvement in stress adaptation. Further functional validation demonstrated that overexpression of GhPDC2 enhanced waterlogging tolerance compared to the WT and mutant lines, as evidenced by improved growth metrics including chlorophyll content, fresh/dry weight, and root length, alongside elevated ethanol accumulation, and increased ADH and PDC2 enzymatic activity. Additionally, GhPDC2 overexpression enhanced ROS scavenging capacity. Conversely, silencing GhPDC2 in cotton significantly compromised the development of adaptive morphological traits under waterlogging. Collectively, these findings demonstrate that GhPDC2 modulates anaerobic metabolism during waterlogging by alleviating energy crises through ethanol accumulation, mitigating ROS production, and ultimately confers oxidative protection.