Untargeted Metabolomics and Bioactivity Screening of Mycelial Culture Extracts from Marasmioid Fungi.

Basidiomycota is a cosmopolitan fungal phylum recognized for its nutritional properties and as a natural source of bioactive compounds. Within this group, the family Marasmiaceae Roze ex Kühner remains comparatively understudied. In this study, we performed a metabolic characterization and bioactivity screening of four marasmioid fungal strains using untargeted metabolomic and bioinformatic tools to analyze the metabolic profiles of broth extracts from strains Montiel04, FGR1289, FGR1276, and CC45, detecting 296, 447, 167, and 99 spectrometric features (m/z_RT), respectively. The extracts exhibited notable antibacterial activity, particularly against Clavibacter michiganensis and Erwinia persicina, with strain FGR1289 demonstrating the highest efficacy. Furthermore, extracts from strains FGR1289 and FGR1276 exhibited significant antioxidant capacity against ABTS+, DPPH, and galvinoxyl radicals. Pathway enrichment analysis identified putative metabolic pathways involved in organic acid biosynthesis, amino acid metabolism, and butyrate, which may contribute to the observed bioactivities. These findings highlight the marasmioid group as a promising reservoir of bioactive metabolites and support further research on their potential pharmaceutical and agricultural applications.