Aflatoxigenic Aspergillus modulates aflatoxin-B1 levels through an antioxidative mechanism

Bwalya Katati*, Stan Kovacs, Henry Njapau, Paul W. Kachapulula, Bas Zwaan, Anne van Diepeningen, Sijmen Schoustra

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Scopus)

Abstract

Aflatoxins (AFs) are considered to play important functions in species of Aspergillussection Flavi including an antioxidative role, as a deterrent against fungivorous insects, and inantibiosis. Atoxigenic Flavi are known to degrade AF-B1 (B1). To better understand the purposeof AF degradation, we investigated the degradation of B1 and AF-G1 (G1) in an antioxidative rolein Flavi. Atoxigenic and toxigenic Flavi were treated with artificial B1 and G1 with or without theantioxidant selenium (Se), which is expected to affect levels of AF. After incubations, AF levels weremeasured by HPLC. To estimate which population would likely be favoured between toxigenicand atoxigenic Flavi under Se, we investigated the fitness, by spore count, of the Flavi as a result ofexposure to 0, 0.40, and 0.86 μg/g Se in 3%-sucrose cornmeal agar (3gCMA). Results showed thatlevels B1 in medium without Se were reduced in all isolates, while G1 did not significantly change.When the medium was treated with Se, toxigenic Flavi significantly digested less B1, while levels ofG1 significantly increased. Se did not affect the digestion of B1 in atoxigenic Flavi, and also did notalter levels of G1. Furthermore, atoxigenic strains were significantly fitter than toxigenic strains at Se0.86 μg/g 3gCMA. Findings show that while atoxigenic Flavi degraded B1, toxigenic Flavi modulatedits levels through an antioxidative mechanism to levels less than they produced. Furthermore, B1was preferred in the antioxidative role compared to G1 in the toxigenic isolates. The higher fitnessof atoxigenic over toxigenic counterparts at a plant non-lethal dose of 0.86 μg/g would be a usefulattribute for integration in the broader biocontrol prospects of toxigenic Flavi.
Original languageEnglish
Article numberjof9060690
Number of pages19
JournalJournal of Fungi
Volume9
Issue number6
DOIs
Publication statusPublished - 20 Jun 2023

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