Location: Toxicology & Mycotoxin ResearchTitle: Fungal chemical warfare: how secondary metabolites influence relationships in maize associated fungi
Submitted to: Fungal Genetics Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 12/8/2021
Publication Date: N/A
Technical Abstract: Contamination of maize by mycotoxins is a global problem affecting food safety and security worldwide. Exposure to mycotoxins can lead to a variety of health problems for both humans and animals. Additionally, there is a large economic cost associated with mycotoxin contamination including reduced product market value and lower animal performance. Two mycotoxins commonly contaminating maize are aflatoxin and fumonisin that are produced by the plant pathogens Aspergillus flavus and Fusarium verticillioides, respectively. Multiple studies have found these pathogens together in field colonized maize but have not examined their direct interaction. Another maize-associated fungus that comes into contact with these mycotoxigenic fungi is the endophyte Sarocladium zeae. Pyrrocidine, produced by S. zeae, was recently shown to inhibit fumonisin production in F. verticillioides. In this study, we evaluated pairwise interactions between A. flavus, F. verticillioides and S. zeae. Our results indicated that when grown in proximity, F. verticillioides can inhibit the growth of A. flavus, and that fumonisin is the primary cause of this growth inhibition. While F. verticilliodes inhibition was not seen with aflatoxin, production of both fumonisin and aflatoxin was suppressed in the presence of the antagonist’s primary mycotoxin. The responses also varied with A. flavus demonstrating a localized response to fumonisin where a more general response was seen with aflatoxin treated F. verticillioides. While pyrrocidine had no effect on aflatoxin production, S. zeae produced other unidentified compound(s) that inhibit the growth of both A. flavus and F. verticillioides. This compound(s), unlike pyrrocidine, inhibits aflatoxin production in A. flavus. This work gives insights into the ecological role of fungal secondary metabolites in the interspecies battle for resource acquisition.