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

## TL;DR

This study identifies a biocontrol strain, LYH8, that effectively reduces wheat disease caused by Fusarium graminearum and lowers harmful mycotoxin levels.

## Contribution

The novel contribution is the identification and characterization of Bacillus velezensis LYH8 as a potent biocontrol agent against Fusarium head blight.

## Key findings

- LYH8 inhibited F. graminearum mycelial growth by 43% and caused morphological abnormalities.
- Treatment with LYH8 reduced wheat disease severity by 75–85% and decreased DON and D3G levels by 20–22%.
- Transcriptome analysis showed LYH8 affects pathogen growth via amino acid, ribosomal, and carbon metabolism pathways.

## Abstract

Fusarium head blight (FHB), caused by Fusarium 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 of F. graminearum, with an inhibition rate of 43%, and induced morphological abnormalities such as hyphal swelling and shrinkage. Based on 16S rRNA and gyrB gene sequencing and phylogenetic analysis, LYH8 was identified as Bacillus 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.