Fusaric acid detoxification mediates interspecies interactions for sustainable Fusarium wilt disease management

Microbial biocontrol agents (BCAs) play a critical role in maintaining plant health by antagonizing pathogens. However, most research has focused on direct suppression mechanisms (e.g., antibiosis and competition), while the neutralization of mycotoxin for disease management remains unexplored. Here, we report that a fungal BCA, Trichoderma harzianum (Th), subverts Fusarium verticillioides (Fv) infection via a fusaric acid (FSA) detoxification process in maize. Salicylate hydroxylase was found to detoxify FSA into an almost non-toxic metabolite, 10OH-FSA. This mechanism not only neutralized the pathogenicity of Fv but also mediated interspecies interactions contributing to Fv suppression. Additionally, FSA detoxification exhibited broad applicability in controlling different Fusarium diseases in maize, tomato, and wheat. More profoundly, Th-induced FSA detoxification activity in the rhizosphere could stimulate the growth of other FSA detoxification-capable microbes, amplifying disease suppression through ecological cross-talk. These findings unveil an ecological tactic employed by BCAs to manage soil-borne Fusarium wilt disease.