Transcriptomic insights into common defense mechanisms of Pleurotus ostreatus, Agaricus bisporus, and Lentinula edodes against Pseudomonas tolaasii-induced browning.

Abstract

This study investigated gene expression patterns associated with the browning of mushroom fruiting bodies caused by Pseudomonas tolaasii infection. To address this, Pleurotus ostreatus, Agaricus bisporus, and Lentinula edodes were inoculated with P. tolaasii, and morphological changes were examined, followed by transcriptome analysis to identify common and differentially expressed genes across the three species. Hydrophobin and glycoside hydrolase family 13 genes, associated with α-glucan metabolism and cell wall-related processes, were commonly downregulated, whereas laccase- and histidine kinase-related genes involved in melanin biosynthesis were significantly upregulated (log2 fold change ≥ 2, p ≤ 0.05). Notably, laccase induction represented a conserved transcriptional response to P. tolaasii infection, although the magnitude of induction varied among species. These findings provide molecular evidence linking mushroom browning to the transcriptional activation of defense-related genes and highlight laccase as a key, yet species-dependent, component of the response to P. tolaasii infection.