Integrating genomics and targeted metabolite profiling to elucidate disease-suppression mechanisms of Bacillus velezensis GFB08
Journal
Current Research in Microbial Sciences
Journal Volume
9
Start Page
Article number:100503
ISSN
2666-5174
Date Issued
2025-10-30
Author(s)
Yi-Tun Cho
Bo-Wei Wang
Yi-Chen Tsai
Hao-Yung Wang
Yu-Liang Yang
Abstract
Welsh onion cultivation in Taiwan faces a significant threat from a foliar disease complex caused by three major pathogens: Stemphylium vesicarium, Colletotrichum spaethianum , and C. circinans . As an alternative to conventional fungicides, the biocontrol agent Bacillus velezensis GFB08 was systematically characterised through an integrated genomic and targeted metabolite profiling approach. The 3.89 Mbp genome harbored biosynthetic gene clusters for key lipopeptides, and comparative genomics revealed a mersacidin-like BGC, a feature variably present in B. velezensis, indicating enhanced antimicrobial potential. Metabolite profiling identified fengycin and bacillomycin D as the primary antifungal compounds. Bioassays demonstrated that purified fengycin exhibited potent, broad-spectrum activity against all three pathogens, while bacillomycin D displayed species-specific effects, significantly inhibiting only C. spaethianum . The interaction between these two lipopeptides was determined to be additive, not synergistic, against C. spaethianum . Furthermore, volatile organic compounds (VOCs) from GFB08 significantly inhibited C. spaethianum while unexpectedly stimulating the growth of C. circinans , highlighting the complexity of its biocontrol mechanisms. Among these VOCs, acetic acid was highly effective, providing complete inhibition at a concentration of 0.1 µL/mL. The strain also demonstrated a significant plant growth-promoting effect, which was limited to the seed stage. This study provides the first integrative genomic–metabolite–functional characterization of a Welsh onion biocontrol strain GFB08, clarifying its multi-modal mechanisms and highlighting the role of mersacidin-associated genomic features and pathogen-specific VOC responses in biocontrol efficacy.
Subjects
Bioactive secondary metabolites
Biocontrol agent
Comparative genomic analysis
Fermentation optimization
Plant growth promotion
SDGs
Publisher
Elsevier Ltd
Type
journal article