Metabolomic Profiling of Fungal Pathogens Responsible for Root Rot in American Ginseng.

Ginseng root is an economically valuable crop in Canada at high risk of yield loss caused by the pathogenic fungus formerly known as . While this pathogen has been well-characterized from morphological and genetic perspectives, little is known about the secondary metabolites it produces and their role in pathogenicity. We used an untargeted tandem liquid chromatography-mass spectrometry (LC-MS)-based approach paired with global natural products social molecular networking (GNPS) to compare the metabolite profiles of virulent and avirulent strains. The ethyl acetate extracts of 22 strains and closely related species were analyzed by LC-MS/MS. Principal component analysis of LC-MS features resulted in two distinct groups, which corresponded to virulent and avirulent strains. Virulent strains produced more types of compounds than the avirulent strains. The previously reported antifungal compound radicicol was present. Additionally, a number of related resorcyclic acid lactones (RALs) were putatively identified, namely pochonins and several additional derivatives of radicicol. Pochonins have not been previously reported in spp. and have documented antimicrobial activity. This research contributes to our understanding of natural products and its pathogenic relationship with ginseng.