Employing Bacillus lipopeptides for sustainable management of phytopathogenic fungi in horticulture

The increasing demand for food production, coupled with yield losses of up to 25% in fruits and vegetables caused by phytopathogenic fungi, highlights the urgent need for sustainable alternatives to chemical fungicides. This review investigates the role of biosurfactants, particularly cyclic lipopeptides (CLPs) produced by Bacillus spp., in the biological control of plant pathogens in horticulture. A systematic literature search (Scopus and Web of Science, 2020–2025) resulted in 57 studies, complemented by earlier references, and a keyword co-occurrence analysis confirmed the central role of CLPs in biocontrol. From these studies, multiple antifungal mechanisms were identified: iturins bind to sterols in fungal membranes, forming pores that cause ion leakage and cell death; fengycins disrupt membrane integrity, inhibit spore germination, and elicit systemic resistance; and surfactins, though weaker in direct inhibition, act as strong elicitors of plant defense signalling. Quantitative evidence demonstrates significant pathogen suppression: B. siamensis reduced Fusarium oxysporum growth by over 90%; B. velezensis suppressed Verticillium by 92.9%; and lipopeptides lowered potato black rot severity from 55.2% to 26.5%. Beyond antifungal activity, CLPs enhance plant resistance by stimulating defense-related enzymes and improve fruit quality and postharvest shelf life. Overall, Bacillus-derived lipopeptides represent powerful, eco-friendly tools to reduce agrochemical dependence, and mitigate resistance in phytopathogenic fungi. This review synthesises current knowledge on their mechanisms, applications, and production challenges, reinforcing their potential as sustainable alternatives to conventional pesticides and the need for technological advances to overcome existing barriers.