AbZnF-GATA transcription factor synergizes with AbCYPs to regulate the browning mechanism of Agaricus bisporus

Agaricus bisporus (A. bisporus) is susceptible to postharvest infestation by pathogens, leading to browning and significant losses. AbZnF-GATA transcription factors and AbCYPs genes were found to respond positively during browning of A. bisporus in previous transcriptomic data, but their transcriptional regulatory roles in browning of A. bisporus are unknown. The aim of this study was to elucidate the biological functions of AbZnF-GATA transcription factors with nuclear membrane co-localization and AbCYPs genes, and their mechanisms of action during the browning process of A. bisporus. It was shown that AbZnF-GATA, AbCYP52A, AbCYP4F12 and AbCYP547A could cause severe browning in A. bisporus through Agrobacterium-mediated transient overexpression. A possible regulatory relationship between GATA transcription factors and AbCYPs during browning of A. bisporus. In this study, it confirmed that AbZnF-GATA activates AbCYP52A and AbCYP4F12 expression through a bidirectional regulatory mechanism, while inhibiting the transcriptional activity of AbCYP547A. It was further found that AbZnF-GATA could promote soluble quinone accumulation and on the other hand drive the browning phenotype by synergistically upregulating the catalytic activities of polyphenol oxidase (PPO), tyrosinase (TYR) and laccase (LAC). This study provides novel molecular targets for the subsequent development of postharvest browning inhibitors for A. bisporus.