FoHsf1 reprograms central metabolism via caffeine and vitamin D₂ to modulate development and virulence of Fusarium oxysporum on Polygonatum kingianum

Abstract

Root rot has severely affected the yield and quality of Polygonatum kingianum , and Fusarium oxysporum has been identified as the primary causal agent. To explore virulence mechanisms of this pathogen, we performed a functional characterization of FoHsf1 , a gene encoding a heat shock transcription factor in F. oxysporum . A FoHsf1 deletion mutant ( ΔFoHsf1 ) was constructed by homologous recombination, and a complemented isolate ( ΔFoHsf1 -C) was generated by reintroducing the full-length gene. Phenotypic assays were performed to evaluate mycelial growth, conidiation, and virulence on P. kingianum . Transcriptomic and metabolomic analyses were conducted to identify differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) associated with FoHsf1 deletion. Exogenous supplementation with caffeine and vitamin D 2 was carried out to assess the rescue of growth and virulence defects in ΔFoHsf1 . We found that ΔFoHsf1 exhibited significant defects in mycelial growth, conidiation, and virulence relative to the wild-type (WT) and ΔFoHsf1 -C. Integrated transcriptomic and metabolomic profiling demonstrated that DEGs and DAMs were predominantly enriched in carbohydrate and amino acid metabolism pathways. More importantly, the metabolite abundance of caffeine and vitamin D 2 was significantly reduced in ΔFoHsf1 ; exogenous application of these two metabolites partially restored fungal growth and virulence. These findings suggest that FoHsf1 regulates fungal development and virulence by modulating core metabolic pathways. Our results advance the understanding of the molecular mechanism underlying FoHsf1 -mediated virulence of F. oxysporum and offer potential targets for managing this disease. Not applicable.