Scientific Study

Aspergillus flavus is a soil fungus that commonly invades peanut seeds and often produces the carcinogenic aflatoxins. Under favorable conditions, the fungus-challenged peanut plant produces and accumulates resveratrol and its prenylated derivatives in response to such invasion. These prenylated stilbenoids are considered peanut antifungal phytoalexins. However, the mechanism of peanut-fungus interaction has not been sufficiently studied. We used pure peanut stilbenoids, arachidin-1, arachidin-3, and chiricanine A to study their effect on the viability and metabolite production by several important toxigenic Aspergillus species. Significant reduction, or virtually complete suppression of aflatoxin production was revealed in feeding experiments in A. flavus, A. parasiticus, and A. nomius. Changes in morphology, spore germination and growth rate were observed on A. flavus exposed to selected peanut stilbenoids. Elucidation of the mechanism of aflatoxin suppression by peanut stilbenoids could provide strategies for preventing plant invasion by the fungi that produce aflatoxins.