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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Antimicrobials, Resistance and Chemotherapy
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1480920

Pyrrocidines A and B demonstrate synergistic inhibition of Fusarium verticillioides growth

Provisionally accepted
Lily W Lofton Lily W Lofton 1,2*Quentin D Read Quentin D Read 3Hailey L Hamilton Hailey L Hamilton 2Anthony E Glenn Anthony E Glenn 2Jaci A Hawkins Jaci A Hawkins 2Trevor R Mitchell Trevor R Mitchell 2Scott E Gold Scott E Gold 2
  • 1 Department of Plant Pathology, College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, United States
  • 2 Toxicology and Mycotoxin Research Unit, United States National Poultry Research Center, Agricultural Research Service, United States Department of Agriculture, Athens, United States
  • 3 Southeast Area, Agricultural Research Service, United States Department of Agriculture, Raleigh, United States

The final, formatted version of the article will be published soon.

    Fusarium verticillioides – a mycotoxigenic fungus and food safety threat – coinhabits maize kernels with Sarocladium zeae. This protective endophyte produces secondary metabolites of interest, pyrrocidines A and B, which inhibit the growth of F. verticillioides and specifically block fumonisin biosynthesis. Previous transcriptomic analyses found FvZBD1 (FVEG_00314), a gene adjacent to the fumonisin biosynthetic gene cluster, to be induced over 4,000-fold in response to pyrrocidine challenge. Deletion of FvZBD1 resulted in dramatic increases in fumonisin production (FB1 > 30-fold). Here, using pyrrocidine dose-response assays, we discovered a potent synergy between pyrrocidines A and B, where they functioned powerfully together to inhibit F. verticillioides growth. Further, results provided evidence that FvZBD1 confers partial tolerance to pyrrocidines, particularly pyrrocidine A, and that pyrrocidine functions through FvZBD1 to effectively eliminate fumonisin biosynthesis. Additionally, we showed that the FvABC3 (FVEG_11089) mutant, earlier described as hypersensitive to pyrrocidine, is particularly sensitive to pyrrocidine B. Thus, pyrrocidine A and B show different target specificity (FvZBD1 or FvABC3) and synergistic action. These findings will help inform the optimization of maximally efficacious S. zeae strains for eliminating F. verticillioides colonization and fumonisin contamination in maize cropping systems. This novel study contributes significantly to our knowledge of competitive microorganism relationships and the role of secondary metabolites in antagonistic fungal-fungal interactions.

    Keywords: Fusarium verticillioides, Sarocladium zeae, Fumonisin, pyrrocidine, Maize, biological control, secondary metabolites, Fungal-fungal interactions

    Received: 14 Aug 2024; Accepted: 09 Dec 2024.

    Copyright: © 2024 Lofton, Read, Hamilton, Glenn, Hawkins, Mitchell and Gold. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Lily W Lofton, Department of Plant Pathology, College of Agricultural and Environmental Sciences, University of Georgia, Athens, 30602, Georgia, United States

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