Fengycin, a lipopeptide synthesized by Bacillus species, exhibits pronounced antifungal activity; however, its low production titer remains a primary constraint to broader application. Global regulatory factors constitute key actionable targets for enhancing microbial synthesis. Here, we verified the ability of Bacillus amyloliquefaciens TF28 to produce fengycin with potent inhibitory activity. Transcriptomic analysis identified five global regulators linked to fengycin biosynthesis in this strain. Following their overexpression, fermentation kinetics indicated that while these regulators generally did not affect glucose utilization, each exerted a distinct effect on cell growth and fengycin production. Specifically, degQ overexpression increased fengycin production to 116.0 mg/L, corresponding to a 23.40% increase relative to the strain without degQ overexpression, whereas overexpression of degU, sigmaH, phoP, and abrB reduced it. Moreover, degQ and abrB overexpression modulated the expression of key fengycin synthetase genes, including fenA and fenB. Collectively, these findings establish that degQ, degU, sigmaH, phoP, and abrB functionally regulate fengycin biosynthesis in B. amyloliquefaciens TF28, providing a conceptual framework for the rational design of engineered strains with enhanced fengycin productivity.

Corn stalk rot, caused by Fusarium graminearum, severely threatens corn production, while chemical fungicides lead to resistance and environmental risks. Thus, exploring environmentally friendly biocontrol agents is crucial. Though Bacillus polyketones have antifungal activity, their active components, corn stalk rot biocontrol potential and rhizosphere impacts remain unclear. This study isolated polyketones from Bacillus velezensis DJ1, assessed their antifungal activity and mechanism against F. graminearum, verified greenhouse efficacy, analyzed rhizosphere microbiota, and identified active components via HPLC-HDMS Q-TOF. The results showed that DJ1 polyketones showed dose-dependent inhibition by disrupting F. graminearum’s mycelium and membrane, with 44.33% greenhouse control efficacy. They did not disturb rhizosphere balance, only increasing Bacteroidota and DYGX01, and the active components were difficidin and bacillaene. These findings confirm DJ1 polyketones as promising eco-friendly biocontrol agents, providing a new strategy for sustainable corn stalk rot management.