Fusarium sacchari 14-3-3 Protein FsBmh1 Sequesters a Novel Elicitor FsEcm33 to Evade Host Immunity

Fusarium sacchari, the causal agent of pokkah boeng disease (PBD), is a globally devastating pathogen of sugarcane that causes substantial economic losses. During infection, the fungus employs elicitors to induce necrosis in plant tissues, thereby enhancing pathogen fitness. However, the key elicitors in F. sacchari and the mechanism by which plants recognize them remain unclear. Here, we identified a predicted glycosylated phosphatidylinositol (GPI)-anchored protein FsEcm33 as an elicitor that activates plant immunity. FsEcm33 is perceived in the apoplast of Nicotiana benthamiana by the receptor-like protein NbRE02 and induces cell death in a manner that requires the co-receptors NbBAK1 and NbSOBIR1. Purified FsEcm33 triggers basal immune responses in N. benthamiana and enhances disease resistance in multiple plant species, including sugarcane, rice, wheat, and star anise. In F. sacchari, FsEcm33 localizes to the cell surface, where its recognition by the host limits pathogen colonization. Notably, FsEcm33 specifically interacts with a 14-3-3 protein, FsBmh1, which reduces its accumulation at the fungal cell surface, suggesting a spatial sequestration mechanism that helps F. sacchari evade host immunity. Together, these findings establish FsEcm33 as a cell-surface elicitor perceived by NbRE02 and reveal an evolutionary strategy in which FsBmh1 sequesters FsEcm33 to evade host recognition and facilitate infection in F. sacchari.