Lipopeptide culture filtrates from Bacillus spp. provide effective protection to wheat against the foliar pathogen Zymoseptoria tritici.

This article investigates the potential of cell-free culture filtrates (CFCFs) from two Bacillus subtilis group strains—Bacillus velezensis GA1 and Bacillus sp. III1—to control Zymoseptoria tritici, a major fungal pathogen causing Septoria tritici blotch (STB) in wheat. Greenhouse experiments demonstrated that foliar application of these CFCFs significantly reduced disease severity by over 90%, with in vitro and in planta assays confirming strong inhibition of spore germination and fungal growth. Chemical analyses revealed distinct lipopeptide profiles in the CFCFs, with GA1 producing iturin A alongside surfactins and fengycins, and III1 producing mojavensin A (an iturin family member) with surfactins and fengycins, suggesting different iturin subfamilies contribute to antifungal activity. The study highlights the promise of Bacillus-derived CFCFs as sustainable biofungicides for wheat disease management, while noting challenges related to large-scale production and formulation stability.