Enhanced activity of strobilurin and fludioxonil by using berberine and phenolic compounds to target fungal antioxidative stress response.
Authors:
Kim, J.H. Campbell, B.C. Mahoney, N. Chan, K.L. Molyneux, R.J. May, G.S. USDA, ARS
Source:
Letters in applied microbiology. 2007 Aug., v. 45, no. 2 Oxford, UK : Blackwell Publishing Ltd, p. 134-141.
NALT Subjects:
Aspergillus Penicillium Saccharomyces cerevisiae
Other Subjects:
antioxidative stress system phenolics antifungal alkaloid
Issue Date:
Aug-2007
Abstract:
Identify natural products that effectively target antioxidative signal transduction/stress response systems [i.e., mitogen-activated protein kinase (MAPK) pathway, mitochondrial superoxide dismutase (Mn-SOD)] of fungi. Enhance activity of strobilurin or fludioxonil with discovered compounds. Enhancement of antifungal activity of strobilurins, inhibitors of complex III of the mitochondrial respiratory chain, was tested using berberine hemisulfate and different phenolic compounds. The Saccharomyces cerevisiae sod2Δ, a deletion mutant lacking Mn-SOD gene, was highly sensitive to berberine and veratraldehyde. Functional complementation analysis verified these compounds target Mn-SOD. Activity of strobilurin (25-50 μmol l⁻¹) was elevated on most aspergilli and Penicillium expansum by co-application with berberine or veratraldehyde (2-4 mmol l⁻¹). These compounds also prevented Aspergillus fumigatus MAPK mutants (sakAΔ and mpkCΔ) from escaping toxicity of fludioxonil (a phenylpyrrole fungicide potentiated by the MAPK pathway), a typical phenotype of fungal MAPK mutants. Strobilurin activity or prevention of fungal escape from fludioxonil toxicity can be enhanced by co-application of certain alkaloids or phenolics. Natural products can be used to target cellular stress response systems in fungal pathogens and serve as alternatives/additives to commercial antifungal agents.
