PpWRKY23 modulates hydrogen peroxide contents to inhibit flesh browning in peach

Browning is a significant issue in fresh-cut peach fruits, leading to nutrient loss, flavor deterioration, and reduced consumer acceptance. Despite its economic importance, the molecular mechanisms governing the browning process remain largely unclear. In this study, comparative transcriptome and metabolome analyses between the browning-resistant variety ‘QZMT’ (Qing Zhou Mi Tao) and the browning-susceptible variety ‘QBT’ (Qiu Bai Tao) revealed that browning resistance in ‘QZMT’ is primarily attributed to low polyphenol and flavonoid contents, coupled with low polyphenol oxidase (PPO) activity and high hydrogen peroxide (H₂O₂) content. Moreover, PpWRKY23 was identified as a key regulator activated by fresh-cut signaling. Transient overexpression of PpWRKY23 in peach resulted in the increased H₂O₂ content, thereby browning alleviation. PpWRKY23 directly bound to the W-box element in promoter region of PpRBOHB, activating its expression and leading to increased H₂O₂ production. These findings deepen our understanding of peach flesh browning and offer potential targets for improving fruit quality.