Identification of the Biocontrol Effect of Bacillus velezensis LYH8 Against Fusarium Head Blight of Wheat

Fusariumhead blight (FHB), caused byFusarium graminearum, is a fungal disease that severely affects wheat. The mycotoxins it produces, such as deoxynivalenol (DON), pose serious risks to human and animal health. In this study, a biocontrol strain, LYH8, was isolated from local sources in Jingzhou, Hubei Province. Plate confrontation assays demonstrated that LYH8 effectively inhibited the mycelial growth ofF. graminearum, with an inhibition rate of 43%, and induced morphological abnormalities such as hyphal swelling and shrinkage. Based on16S rRNAandgyrBgene sequencing and phylogenetic analysis, LYH8 was identified asBacillus velezensis. In vivo experiments showed that disease severity in wheat coleoptiles and spikes was significantly reduced by treatment with LYH8 by 75–85%, and the accumulation of DON and its deoxynivalenol-3-glucoside (D3G) in grains was decreased by 20–22%. Further transcriptome analysis revealed that it affects pathogen growth by regulating amino acid biosynthesis, ribosomal biosynthesis, carbon metabolism pathways, and the catalytic activities of related genes. In summary, LYH8 significantly controlled FHB through multiple mechanisms, including inhibiting mycelial growth, reducing infection, and blocking toxin synthesis, demonstrating strong biocontrol potential.