Identification and characterization of novel fumonisin-detoxifying enzymes
Abstract
Fumonisins are a family of mycotoxins produced by Aspergillus and Fusarium spp. fungi whose contamination of food and feed presents a worldwide agroeconomic threat. Certain Aspergillus spp. post-biosynthetically convert their B series fumonisins (FB) to less toxic forms, replacing their terminal amine with a ketone (FPy) or hydroxyl (FLa). AnFAO is an enzyme responsible for FB deamination in Aspergilli, however FLa-generating enzymes remain unknown. Additionally, Fusarium’s potential fumonisin-detoxifying ability has not been characterized. Herein, I identify FLa-generating enzymes (FUM13) and characterize the fumonisin-deaminating activity of an F. verticillioides AnFAO homolog (FvFAO). A. niger and F. verticillioides FUM13 isoforms reduced FPy fumonisins to FLa forms overnight with low efficiency. I also report that FvFAO deaminates FB fumonisins ~5x less efficiently than AnFAO. These results provide insight into differences in fumonisin self-protection mechanisms between these genera, and may lead to the development of new tools for treatment of fumonisin-contaminated food and feed.