P-066 - Unlocking the antibacterial potential of specialty mushroom compounds for sustainable disease management

Bacterial blotch, caused by Pseudomonas species, is a major disease affecting white button mushrooms (Agaricus bisporus) and results in significant crop losses. Previous findings suggest that shiitake (Lentinula edodes) and maitake (Grifola frondosa) mushrooms suppress bacterial blotch growth via in vitro inhibition assays, suggesting the presence of inhibitory compounds. This study investigates the potential of mushroom derived compounds to inhibit blotch causing bacteria through bioassay-guided extraction, partitioning, and fractionation. Extracts from L. edodes and G. frondosa were obtained using 80% aqueous methanol, which were subsequently partitioned against hexane, ethyl acetate, and butanol. Lyophilized dry weight yields from fresh mushrooms ranged between approximately 7% and 11%, while the solvent partitions resulted in yields ranging from approximately 0.5% to 18%, reflecting substantial variability in chemical composition across the partitions. Initial disk diffusion assays demonstrated inhibition but were inconsistent. Future work will characterize active compounds by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS), resazurin inhibition assays, and the evaluation of their efficacy in vitro and ex vivo on A. bisporus caps to assess their potential for bacterial blotch management. This research aims to advance sustainable disease control strategies by identifying natural antimicrobial compounds that may reduce reliance on synthetic chemical interventions in crop production.