To investigate the antimicrobial active substances of the endophytic fungus  Achaetomium sophora  HY17 from  Sophora alopecuroides  in the co-culture system based on UPLC-MS/MS technology

The secondary metabolites produced by endophytic fungi of medicinal plants have a broad potential in the field of biological control. Metabolomics and microbial co-culture technology are the common and crucial methods for exploring microbial secondary metabolites. The endophytic fungus A. sophora HY17, isolated from the medicinal plant Sophora alopecuroides , was used in this study to investigate the dynamic changes in secondary metabolites during its interaction with the pathogenic fungi B. cinerea HM. And the metabolites were quantified with Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and metabolomics. The results show that A. sophora HY17 contained various metabolites such as alkaloids, flavonoids, phenolic acids, terpenoids, lignans, and coumarin. Further, through the established metabolomics model, sophoridine, sophocarpine, matrine, oleoylethanolamine, 3-hydroxyanthranilic acid, chalcone, cynaroside, daidzein, vitexin, and 1-tetralone were identified to play significant antifungal roles in the interaction between the two fungi. The KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis revealed a significant enrichment of differential secondary metabolites in the phenylalanine metabolic pathway throughout the interaction. This study provides a theoretical basis for identifying antifungal secondary metabolites produced by plant endophytic fungi and designing new biocontrol agents.