Mechanism of Elevated CO2 Delaying Senescence of Postharvest Agaricus bisporus by Regulating Energy Metabolism: Insights from Metabolomics

Agaricus bisporus (A. bisporus) is susceptible to rapid postharvest deterioration. Although elevated CO2 (6%) delays senescence, the metabolic mechanisms remain unclear. In this study, untargeted and targeted metabolomic analyses were employed to explore these pathways in A. bisporus. The results revealed that elevated CO2 treatment promoted glycolysis by upregulating Hexokinase (HK), Phosphofructokinase (PFK), and Pyruvate Kinase (PK), accumulating Glucose-6-phosphate (G-6-P) and Fructose-6-phosphate (F-6-P). Concurrently, elevated CO2 treatment upregulated the expression of genes associated with the tricarboxylic acid (TCA) cycle and increased the enzymatic activities of Malate Dehydrogenase (MDH) and Fumarate hydratase (FUM). These changes led to the rapid consumption of key intermediate metabolites (Fumarate (Fum), Malate (Mal), and α-Ketoglutarate (α-KG)), collectively enhancing the efficiency of the TCA cycle. Furthermore, elevated CO2 treatment significantly suppressed the activities of Glutamine Synthetase (GS) and Xanthine Oxidase (XOD), inhibiting the synthesis of Glutamine (Gln) and Pyroglutamate (pGlu) while promoting the accumulation of Hypoxanthine (Hx). This coordinated reprogramming of amino acid metabolism and purine metabolism contributed to improved energy efficiency and enhanced cellular integrity in postharvest A. bisporus. This study elucidates the specific mechanism by which elevated CO2 levels regulate the postharvest energy metabolism of A. bisporus from a metabolomics perspective, providing a theoretical basis for developing strategies to control its postharvest quality.