Genotyping of Benzimidazole-Resistant and Dicarboximide-Resistant Mutations in Botrytis cinerea Using Real-Time Polymerase Chain Reaction Assays

ABSTRACT Botrytis cinerea, an economically important gray mold pathogen, frequently exhibits multiple fungicide resistance. A fluorescence resonance energy transfer-based real-time polymerase chain reaction assay has been developed to detect benzimidazole- and dicarboximide-resistant mutations. Three benzimidazole-resistant mutations—198Glu to Ala (E198A), F200Y, and E198K—in β-tubulin BenA were detected using a single set of fluorescence-labeled sensor and anchor probes by melting curve analysis. Similarly, three dicarboximide-resistant mutations—I365S, V368F plus Q369H, and Q369P—in the histidine kinase BcOS1 were successfully distinguished. Unassigned melting profiles in BenA genotyping assay resulted in the identification of a new benzimidazole-resistant BenA E198V mutation. This mutation conferred resistance to carbendazim as do E198A and E198K mutations. The isolates with BenA E198V mutation showed a negative cross-resistance to diethofencarb, but to a lesser extent than the E198A mutants. A survey ...