Submitted to: Applied Microbiology and Biotechnology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/24/2005
Publication Date: 2/7/2006
Citation: Kim, J.H., Mahoney, N.E., Chan, K.L., Molyneux, R.J., Campbell, B.C. 2006. Controlling food-contaminating fungi by targeting their antioxidative stress-response system with natural phenolic compounds. Applied Microbiology and Biotechnology. 70(6):735-739. Interpretive Summary: Fungi are a problem to U. S. agricultural for a variety of reasons. Many fungi are plant pathogens that can infect crop plants and cause a decline in productivity and harvest. Additionally, some fungi produce toxins that are quite serious to human health. Hence, there is a need to prevent contamination of crop plants by such fungal toxins. Other fungi can directly infect humans causing serious invasive diseases of a variety of organs. The research in this paper presents a new approach to controlling such fungi. Natural, safe compounds are used to weaken the ability of the fungus to respond to treatment with fungicides. In this fashion, the fungus becomes 100 to 1000 times more sensitive to commercial fungicides. This greater sensitivity can reduce the cost for control and the probability of the fungus developing resistance to the fungicide.
Technical Abstract: The antioxidative stress-response system is essential to fungi for tolerating exposure to phenolic compounds. We show how this system can be targeted to improve fungal control by using compounds that inhibit the fungal mitochondrial respiratory chain. Targeting mitochondrial superoxide dismutase (Mn-SOD) with selected phenolic acid derivatives (e.g., vanillyl acetone) resulted in a 100 to 1000 fold greater sensitivity to strobilurin or carboxin fungicides. This synergism is significantly greater with strobilurin than with carboxin, suggesting that complex III of the mitochondrial respiratory chain is a better target than complex II for fungal control, using phenolics. These results show certain natural compounds are effective synergists to commercial fungicides and can be used for improving control of food-borne pathogens. Use of such compounds for fungal control reduces environmental and health risks associated with commercial fungicides, and lowers cost for control and the probability for development of resistance to these fungicides.