Volatilized metabolites produced by soilborne Aspergillus flavus regulate fungal conidiation and production of secondary metabolites

Authors: Castano-Duque, Lina; AHMAD, IMTIAZ - Oak Ridge National Laboratory; Lloyd, Steven; Lebar, Matthew; Carter Wientjes, Carol; MCCARTNEY, NATHANIEL - Pennsylvania State University; ALI, JARED - Pennsylvania State University; Moore, Geromy

Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/11/2025
Publication Date: 1/22/2026
Citation: Castano-Duque, L.M., Ahmad, I., Lloyd, S.W., Lebar, M.D., Carter Wientjes, C.H., Mccartney, N.B., Ali, J.G., Moore, G.G. 2026. Volatilized metabolites produced by soilborne Aspergillus flavus regulate fungal conidiation and production of secondary metabolites. Journal of Chemical Ecology. 52: Article 12. https://doi.org/10.1007/s10886-025-01657-4.
DOI: https://doi.org/10.1007/s10886-025-01657-4

Interpretive Summary: Corn plants are susceptible to infection by fungi such as Aspergillus flavus that have the potential to produce several types of toxins, also known as mycotoxins. One of the most potent mycotoxins known to exist is aflatoxin, a cancer-causing natural compound that impacts the liver. Aflatoxin contaminated corn must be destroyed, causing annual monetary losses in billions of dollars. For growers, it would be helpful to detect the presence of aflatoxin producing fungi at pre-harvest and pre-planting stages. To this end it may be possible to capture volatile organic compounds (VOCs, i.e., gases) these fungi produce while overwintering in the soil or while infecting corn plants. In this study, we acquired A. flavus VOCs. Some of the VOCs produce in high quantities by the fungi growing in the soil were caryophyllene-compounds. Fungal bioassays showed that exposure to caryophyllene increased spore concentration, and modulated aerial hyphae, sclerotia production and decrease mycotoxin production by the fungi. Our results showed insights into the ecological roles that caryophyllene has over A. flavus’ development and metabolism, although their effect on interactions among corn, fungi and other potential organisms are still not fully understood.

Technical Abstract: Corn plants are susceptible to infection by fungi such as Aspergillus flavus that have the potential to produce several types of toxins, also known as mycotoxins. One of the most potent mycotoxins known to exist is aflatoxin, a cancer-causing natural compound that impacts the liver. Aflatoxin contaminated corn must be destroyed, causing annual monetary losses in billions of dollars. For growers, it would be helpful to detect the presence of aflatoxin producing fungi at pre-harvest and pre-planting stages. To this end it may be possible to capture volatile organic compounds (VOCs, i.e., gases) these fungi produce while overwintering in the soil or while infecting corn plants. In this study, we acquired A. flavus VOCs from conidia and sclerotia, while residing in the soil environment, using two VOC capture methods (dynamic flow-through traps and static adsorption fibers). We concluded that soilborne conidia and sclerotia have specific VOC signatures, and sclerotia tend to emit specific VOCs at greater abundance compared to soilborne conidia or fungus-free soil. These sclerotium-specific VOCs include geranyl acetone, caryophyllene compounds, and methanone. Bioassays using toxin producing and non-producing fungi showed that ß-caryophyllene increased spore concentration, and both ß-caryophyllene and caryophyllene oxide were able to modulate aerial hyphae, sclerotia production and decrease aflatoxin, cyclopiazonic acid and ditryptophenaline production in A. flavus strains. Our results show insights into the ecological roles that ß-caryophyllene and caryophyllene oxide have over A. flavus’ development and metabolism, although their effect on multitrophic interactions among corn, fungi and other potential organisms are still not fully understood.