Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/22/2004
Publication Date: 12/15/2004
Citation: Kim, J.H., Campbell, B.C., Mahoney, N.E., Chan, K.L., Molyneux, R.J. 2004. Identification of antifungal phenolics for control of aspergillus flavus using saccharomyces cerevisiae in a model target-gene bioassay. Journal of Agricultural and Food Chemistry. 52(26):7814-7821 Interpretive Summary: Fungal infection of crop plants can result in severe economic losses. Such infections can occur prior to harvest or during storage. Some fungi produce toxic compounds that are of major concern to human health. Control of fungal infections in crop plants is a continuing problem. In this study, we report the effectiveness of some natural plant compounds on controlling fungi. We use yeast as a model in order to gain insights on the genes involved in fungal responses to antifungal compounds. The genetics of yeast is fairly well known compared to other fungi, and thus serves as a good model system. The study shows that one can augment the effectiveness of commercially available fungicides by simply disrupting genes in the fungus that normally provide resistance to the fungicide. These genes can be disrupted with some of the natural compounds tested in this study.
Technical Abstract: The yeast Saccharomyces cerevisiae is used in a newly designed high throughput bioassay system to identify phenolic agents for control of the aflatoxigenic fungus, Aspergillus flavus. Veratraldehyde and cinnamic acid and respective benzoic acid derivatives vanillin, vanillic acid,and vanillyl acetone, and cinnamic acid derivatives o-coumaric acid, m-coumaric acid and p-coumaric acid, showed significant antifungal activities with vanillic and cinnamic acids having the greastest effect in the yeast system with caffeic acid having little to no effect. Antifungal activity levels against A. flavus were similar. This similarity in antifungal activity demonstrated the usefulness of the S. cerevisiae bioassay for screening antifungal compounds. Signal transduction and antioxidative stress responses genes were identified as being important to fungal tolerance to the phenolics. Targeting the antioxidative stress response system in combination with strobilurin-fungicides has a synergistic antifungal effect.