Underlying the early signaling and gene expression of Pleurotus ostreatus mycelia during injury response.

Plants and animals have demonstrated conserved damage defense systems, but the injury response mechanisms in fungi remain largely unexplored. In this study, we investigate the early defensive mechanisms activated by mechanical damage in the basidiomycota Pleurotus ostreatus. Assays of defense enzymes and gene expression in P. ostreatus revealed the role of reactive oxygen species (ROS) and the activation of the mitogen-activated protein kinase (MAPK) signaling pathway in this process. The findings from the defense-related enzyme tests showed that damage enhanced NAD/NADPH-dependent ROS production and endogenous carbon monoxide expression. Additionally, qRT-PCR data provided further evidence for HO generation, highlighting the involvement of MAPK signaling and several early defense components in the damage response of P. ostreatus. Notably, there were differences in the damage response among various pest-resistant strains, with several genes specifically expressed in the pest-resistant strain. Pretreatment of damaged mycelium with N, N'-dimethylthiourea (DMTU, a hydroxyl radical scavenger), diphenyleneiodonium chloride (DPI, a NADPH oxidase inhibitor), or BAPTA (a calcium chelator) significantly inhibited hyphal regeneration and growth. These findings also imply that Ca was an another important signaling molecule in response to wounding. This study provides a more comprehensive holistic view on the damage response of P. ostreatus, and offers valuable references for future research into its biological traits and prospective uses.