Genome-Wide Identification and Expression Pattern Analysis of Polyphenol Oxidase Gene Family in Agaricus bisporus

Polyphenol oxidase (PPO) is the key enzyme in the melanogenesis pathway of enzymatic browning that converts phenolic substrates to quinones and eventually polymerizes to form melanin. In this study, the genome-wide characterization of the Abppo gene family was performed, and six Abppo genes were identified. These genes were divided into three groups based on sequence alignment and phylogenetic analysis, with members of the same group possessing similar motif structures. Expression analysis showed that the Abppo genes demonstrate diverse expression patterns at different growth stages and postharvest storage. In addition, the expression of Abppo genes could be significantly induced by abscisic acid, salicylic acid, methyl jasmonate, and gibberellic acid 3, indicating their potential roles in response to abiotic stresses. These results provide insights into the potential functions of the Abppo gene family, offering a theoretical reference in the future for mushroom breeders.