Extended Data Fig. 10: Proposed model for the mode of action of herbicolin A, which is secreted by ZJU23 in the perithecium microbiome, on Fusarium graminearum.

The biocontrol bacterium P. agglomerans ZJU23 was isolated from F. graminearum perithecium microbiome. ZJU23 showed strong in vitro and in situ antagonism, which was later attributed to the secreted antifungal compound herbicolin A (HA). The HA biosynthetic gene cluster AcbA-J was obtained via horizontal gene transfer from Candidatus Fukatsuia symbiotica. HA binds ergosterol and disrupts the integrity of ergosterol-containing fungal lipid rafts, which subsequently suppresses fungal growth, substantially reducing perithecium formation and virulence of F. graminearum.