Fungicide-induced mutagenesis in Monilinia fructicola and implications for resistance management
G. SCHNABEL (1), F. Chen (1). (1) Clemson University, Clemson, SC, U.S.A.
Azoxystrobin is one of the most widely used fungicides in agriculture with broad spectrum activity against many diseases on many edible crops and ornamentals. It inhibits growth of the target fungus by binding to the Qo site of the cytochrome bc1 complex and thereby interrupting mitochondrial electron transport. In this study, the effect of exposure to sublethal doses of azoxystrobin was investigated in <i>M. fructicola</i> isolates from different geographical locations. Isolates were exposed in weekly transfers of mycelia and spores to a dose gradient of demethylation inhibitor fungicide SYP-Z048 and quinone outside inhibitor fungicide azoxystrobin in solo or mixture treatments for a total of three months. Transposition of a 1500 bp mobile element was observed in the majority of azoxystrobin-treated cultures, but never in the non-fungicide-treated controls and rarely in mycelium treated with demethylation inhibitor fungicides. Variation in multiple microsatellite loci was detected in 2 of 4 isolates subjected to azoxystrobin, indicating mutagenesis on the nucleotide sequence level. Fungicide-induced mutagenesis is a new phenomenon and may enable a pathogen population to quicker adapt to environmental stresses.
View Presentation |
