Integrated transcriptomic and metabolomic analysis reveals mechanisms of hydrogen gas-mediated ascorbic acid maintenance in fresh-cut kiwifruit during cold storage

Hydrogen gas (H₂) has emerged as a novel preservative for postharvest horticultural products, but the molecular mechanisms underlying its anti-senescence effect on fresh-cut produce remain largely elusive. This study investigated the physiological and molecular responses of fresh-cut kiwifruit treated with H₂ fumigation. Results indicated that H₂ treatment significantly delayed postharvest senescence and maintained fruit quality, particularly maintaining a higher ascorbic acid content. Through an integrated transcriptomic and metabolomic analysis, we constructed a comprehensive regulatory network revealing that H₂ modulation primarily targets ascorbate and aldarate metabolism. Transcriptomic profiling revealed that AdAPX3 , which encodes an ascorbate peroxidase was significantly upregulated in response to H₂ treatment. Moreover, network analysis identified the H₂-induced AdbZIP44 was found to be positively correlated with AdAPX3 transcript levels. Electrophoretic Mobility Shift Assays (EMSA) and Dual-Luciferase (LUC) reporter assays confirmed that AdbZIP44 specifically binds to the cis -element of the AdAPX3 promoter and directly activates its transcription, thereby promoting ascorbic acid accumulation. Taken together, our study uncovers a novel H₂-induced AdbZIP44-AdAPX3 regulatory module that governs ascorbic acid accumulation in fresh-cut kiwifruit, providing new molecular insights into H₂-mediated quality preservation in postharvest horticultural products.