Parallel evolution of multiple mechanisms for demethylase inhibitor fungicide resistance in the barley pathogen Pyrenophora teres f. sp. maculata.

Parallel evolution of multiple mechanisms for demethylase inhibitor fungicide resistance in the barley pathogen Pyrenophora teres f. sp. maculata. Fungal Genet Biol. 2020 Oct 06;:103475 Authors: Mair WJ, Thomas GJ, Dodhia K, Hills AL, Jayasena KW, Ellwood SR, Oliver RP, Lopez-Ruiz FJ Abstract The fungal pathogen Pyrenophora teres f. sp. maculata (Ptm), responsible for spot-form of net blotch (SFNB), is currently the most significant disease of barley in Australia and a major disease worldwide. Management of SFNB relies heavily on fungicides and in Australia the demethylase inhibitors (DMIs) predominate. There have been sporadic reports of resistance to DMIs in Ptm but the mechanisms remain obscure. Ptm isolates collected from 1996 to 2019 in Western Australia were tested for fungicide sensitivity levels. Decreased sensitivity to DMIs was observed in isolates collected after 2015. Resistance factors to tebuconazole fell into two classes; moderate resistance (MR; RF 6-11) and high resistance (HR; RFs 30-65). Mutations linked to resistance were detected in the promoter region and coding sequence of the DMI target gene Cyp51A. Solo-LTR insertion elements were found at 5 different locations in the promoter region. Three different non-synonymous mutations encoded an altered protein with a phenylalanine to leucine substitution at position 489, F489L (F495I in the archetype CYP51A of Aspergillus fumigatus). F489L mutations have also been fou...
Source: Fungal Genetics and Biology - Category: Biology Authors: Tags: Fungal Genet Biol Source Type: research