Antimicrobial Peptide Spampcin ₅₆–₈₆ Controls Fusarium graminearum and Mycotoxin via Membrane Disruption and Oxidative Burst with TRI Repression: A Strategy for Wheat Protection

Fusarium graminearum, the causal agent of Fusarium head blight, poses a serious threat to global cereal production and food safety due to severe mycotoxin contamination. Here, we report that Spampcin₅₆₋₈₆, a marine antimicrobial peptide from Scylla paramamosain, exhibits potent antifungal activity by rapidly inhibiting spore germination and mycelial growth of F. graminearum. Mechanistically, the peptide disrupts fungal cell membrane integrity, leading to extensive leakage of intracellular contents. Concurrently, it induces lethal reactive oxygen species accumulation and membrane lipid peroxidation, triggering a compensatory chitin stress response. Importantly, Spampcin₅₆₋₈₆ markedly suppresses deoxynivalenol (DON) biosynthesis through transcriptional interference with the TRI gene cluster. In planta assays further demonstrate that the peptide delivers robust therapeutic protection against foliar infections and effectively prevents wheat grain spoilage during storage, without causing phytotoxicity. Collectively, these findings highlight Spampcin₅₆₋₈₆ as a promising, safe, and dual-action natural biocontrol agent for managing F. graminearum and mitigating mycotoxin risks.