Lipopeptide-mediated inhibition of Aflatoxin biosynthesis in Aspergillus flavus revealed by DESI-MSI and
Lingxia Peng1, Guohong Zeng1, Ashun Yin1
1College of Life Sciences and Medsicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
Abstract:
Aflatoxin contamination caused by Aspergillus flavus represents a critical threat to global food safety and agricultural sustainability, yet the mechanisms underlying its effective biological control remain poorly understood, particularly at the spatial and metabolic levels. Here, we systematically investigated the biocontrol potential of Bacillus velezensis B2 and elucidated the mechanisms of its bioactive metabolites using an integrated multi-omics strategy. Chemical profiling and purification identified surfactin-iturin complexes (SLCs) as the major antifungal components. Functional assays demonstrated that SLCs completely inhibited spore germination at 160 μg/mL (MIC = 0.125 mg/mL) and exhibited approximately 10-fold higher antifungal potency than the crude extract. SLC treatment also induced severe hyphal deformities, including swelling and membrane disruption. Spatial metabolomics using DESI-MSI revealed a dynamic metabolic shift from m/z 1020 to m/z 1034 during coculture, with surfactin-type metabolites dominating the interspecies interaction interface. Transcriptomic analysis identified 3560 differentially expressed genes (1559 upregulated and 2001 downregulated), and demonstrated that SLCs globally suppressed the aflatoxin biosynthetic pathway by downregulating key genes, including aflK, aflQ, aflP, aflO, aflM, aflE, aflH, and aflT. Consistently, no detectable AFB1 was observed in treated samples (LOD = 0.05 μg/kg). Collectively, these findings demonstrate that SLCs inhibit aflatoxin production through combined structural damage and metabolic reprogramming, and highlight a spatially resolved multi-omics framework for deciphering microbial interactions and developing effective biocontrol strategies in food safety.
Insights
Bacillus velezensis B2 produces surfactin-iturin complexes (SLCs) that effectively control aflatoxin contamination. These compounds disrupt fungal growth and suppress aflatoxin biosynthesis genes, offering a promising biocontrol strategy for food safety.
Area of Science:
- Microbiology
- Food Safety
- Biotechnology
Background:
- Aflatoxin contamination by Aspergillus flavus poses a significant threat to global food safety and agriculture.
- Understanding the mechanisms of biological control agents, particularly at spatial and metabolic levels, is crucial for developing effective strategies.
- The biocontrol potential of Bacillus velezensis B2 and its metabolites against aflatoxin-producing fungi requires detailed investigation.
Purpose of the Study:
- To systematically investigate the biocontrol potential of Bacillus velezensis B2 against aflatoxin contamination.
- To elucidate the mechanisms of action of its bioactive metabolites using an integrated multi-omics approach.
- To understand the spatial and metabolic interactions during microbial biocontrol.
Main Methods:
- Chemical profiling and purification to identify antifungal components, leading to the isolation of surfactin-iturin complexes (SLCs).
- Functional assays to determine the antifungal activity (MIC) and effects on fungal morphology (hyphal deformities).
- Integrated multi-omics strategy, including spatial metabolomics (DESI-MSI) and transcriptomics, to analyze metabolic shifts and gene expression changes.
Main Results:
- Surfactin-iturin complexes (SLCs) were identified as the major antifungal components, completely inhibiting spore germination at 160 μg/mL and causing hyphal deformities.
- Spatial metabolomics revealed dynamic metabolic shifts at the interspecies interaction interface, with surfactin-type metabolites being dominant.
- Transcriptomic analysis showed that SLCs globally suppressed the aflatoxin biosynthetic pathway by downregulating key genes, resulting in undetectable AFB1 levels.
Conclusions:
- Bacillus velezensis B2-derived SLCs effectively inhibit aflatoxin production through combined structural damage and metabolic reprogramming of Aspergillus flavus.
- The study highlights a spatially resolved multi-omics framework for deciphering microbial interactions in biocontrol.
- These findings provide a basis for developing novel and effective biocontrol strategies to enhance food safety and agricultural sustainability.
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