Characterization of extracellular secondary metabolites in Oudemansiella canarii BRM-044600 displaying antifungal activity against the phytopathogen Sclerotinia sclerotiorum.

White mold disease, caused by the phytopathogen Sclerotinia sclerotiorum, provokes severe productivity losses in several economically important crops. Biocontrol agents, especially antagonist filamentous fungi, are environmentally friendly alternatives to the chemical fungicides used in white mold management. The objective of this study was to screen for basidiomycete fungi capable of inhibiting S. sclerotiorum and investigate their bioactive metabolites responsible for antifungal activities. Two out of 17 tested basidiomycete isolates inhibited the mycelial growth of S. sclerotiorum in pair culture experiments on agar plates, namely Oudemansiella canarii BRM-044600 and Laetisaria arvalis ATCC52088. O. canarii BRM-044600 liquid culture filtrate exhibited the greatest antifungal activity and was selected for further investigation. UHPLC-MS analysis suggests that six putative strobilurins, including strobilurin A and/or stereoisomers of this compound (m/z 259.1299, [M + H]+) and three putative strobilurins with m/z 257.1184 ([M + H]+) are likely responsible for the antifungal activity observed in the culture filtrate. For the first time, this work demonstrated the potential of O. canarii for white mold biocontrol and strobilurin production.