Transcriptome-associated metabolomics revealed the regulatory mechanism of Pseudomonas B2 infestation leading to brown spot disease of Agaricus bisporus

Abstract

Pseudomonas-induced browning is a primary factor in postharvest discoloration of Agaricus bisporus (A. bisporus). However, the physiological alterations ensuing Pseudomonas infestation in A. bisporus remain largely unexplored. This study affirmed Pseudomonas B2’s role in causing severe brown spots in A. bisporus. The infestation accelerates tissue browning through heightened phenylalanine aminolyase (PAL), 4-cou­marate-CoA ligase (4CL), polyphenol oxidase (PPO) and tyrosinase (TYR) activities involved in phenolic, flavonoid, and enzymatic reactions. Transcriptome and metabolome analyses revealed changes in amino acid biosynthesis, tryptophan and tyrosine metabolism affecting gene transcription for specific metabolites. The AbPPO1 and AbPPO2 in the tyrosine metabolism pathway are key genes in the development of browning. Nineteen transcription factors closely associated with regulating diseases in Pseudomonas B2-infested mushrooms were identified.