Effectiveness of anaerobic treatment combined with microperforated film packaging in reducing Agaricus bisporus postharvest browning

Postharvest browning of A. bisporus is a significant concern, impacting both its marketability and economic value. This study aims to investigate the effectiveness of short-term anaerobic treatment combined with microperforated film packaging (AT-MAP) in reducing postharvest browning of A. bisporus, with a focus on elucidating its molecular mechanisms. Comprehensive physiological assessments were conducted, including analyses of browning index (BI), polyphenol oxidase (PPO) activity, total phenols, flavonoids, relative electrical conductivity, and malondialdehyde (MDA) content. Additionally, transcriptomic sequencing and real-time quantitative reverse transcription (RT-qPCR) were employed to explore gene expression alterations. Our findings reveal that, compared to both the air control (CK) and microperforated film packaging (MAP), AT-MAP yields enhancements in appearance quality, total phenol, and flavonoid content. Storage with AT-MAP demonstrates a reduction in the browning index, PPO activity, MDA content, and relative conductivity by 11%, 40%, 8%, and 6%, respectively, in comparison to the MAP treatment group. At the molecular level, our analysis identifies a total of 3403 differentially expressed genes (DEGs) in A. bisporus subjected to AT-MAP, comprising 1840 up-regulated genes and 1563 down-regulated genes. AT-MAP downregulates genes in the sphingolipid metabolism pathway, reducing ceramide accumulation and apoptosis. It also diminishes ROS production and enhances cell membrane integrity by modulating genes in the oxidative phosphorylation pathway, particularly those associated with NADH dehydrogenase and cytochrome C reductase. Moreover, AT-MAP curtails melanin and brown pigment formation by suppressing genes involved in the metabolism of phenylalanine, tyrosine, and tryptophan, notably those linked to 3-deoxy-D-arabinoheptulose-7-phosphate (DAHP) synthase. This study contributes insights into the molecular mechanisms underpinning the efficacy of AT-MAP in mitigating postharvest browning in A. bisporus, providing a theoretical foundation for its application in mushroom preservation.