From Function to Omics: Endophytic Beauveria bassiana Promotes Maize Growth by Activating Phytohormone Signaling Pathways under Elevated Carbon Dioxide

Background Several entomopathogenic fungal (EPF) species can colonize and establish symbiotic relationships with plants as endophytes, which affects crop growth under elevated carbon dioxide (eCO₂) concentrations. However, how EPF facilitates eCO ₂ in plants is poorly understood, especially at the transcriptional and metabolic levels. Here, the authors used transcriptomics and metabolomics to examine the effects of a widely used EPF, Beauveria bassiana , on maize growth under eCO ₂ , and how it regulates enzyme activity and endogenous hormone metabolism. Results A significant increase in maize growth, as well as associated enzyme activity and hormones, under eCO ₂ , following B. bassiana colonization, was observed. Omics analyses indicated that these effects may be attributed to the activation of primary metabolic pathways (ZMA01100) and secondary metabolite biosynthesis (ZMA01110), which have been demonstrated to influence plant hormone production and enzyme activity. Conclusions These findings suggest that B. bassiana colonization modulates plant growth under eCO ₂ via regulation of the expression of related genes, and in turn, enzyme activity and hormone metabolism. The findings of the present study offer a theoretical foundation for elucidating the interactions between EPFs and plants under climate change.