Characterization of laboratory mutants of Venturia inaequalis resistant to the strobilurin-related fungicide kresoxim-methyl
| Autor: | Wolfram Köller, Desen Zheng, Gilberto Olaya |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Alternative respiration
Alternative oxidase Cytochrome Genes Fungal Molecular Sequence Data Biology DNA Mitochondrial chemistry.chemical_compound Ascomycota Genetics Amino Acid Sequence DNA Fungal DNA Primers Base Sequence Sequence Homology Amino Acid Cytochrome b Venturia inaequalis Drug Resistance Microbial General Medicine biology.organism_classification Salicylhydroxamic acid Fungicides Industrial Mitochondria Gene Expression Regulation chemistry Biochemistry Apple scab Mutation Strobilurin biology.protein Benomyl |
| Zdroj: | Current Genetics. 38:148-155 |
| ISSN: | 1432-0983 0172-8083 |
| Popis: | Several agricultural fungicides related to the antifungal strobilurins act as inhibitors of respiration by binding to mitochondrial cytochrome b. Two types of laboratory mutants resisting higher doses of the strobilurin-related inhibitor kresoxim-methyl were characterized for Venturia inaequalis, the causal agent of apple scab. Selection of mutagenized conidia by kresoxim-methyl yielded mutants altered in the expression of alternative respiration during the stage of conidia germination. Cytochrome b sequences were not affected in the respective mutants. Selection of conidia on media containing the alternative oxidase inhibitor salicylhydroxamic acid in addition to kresoxim-methyl yielded a highly resistant mutant distinguished by a G143A exchange in cytochrome b. The status of mitochondrial cytochrome b genes remained heteroplasmic, and mitochondria containing wild-type cytochrome b returned to high frequencies during cultivation on inhibitor-free medium. However, continuation of the selection process led to a more pronounced replacement of sensitive by mutated mitochondria. The G143A mutation of cytochrome b causing resistance of V. inaequalis to a strobilurin-related inhibitor has been reported previously for mouse mitochondria; and a permanent G143A exchange rendering naturally resistant mitochondria has been reported for the strobilurin-producing basidiomycete Mycena galopoda and for the sea urchin Paracentrotus lividus. At the corresponding position, alanine was also present in chloroplast cytochrome b6 exhibiting low binding of strobilurin-related inhibitors. The mutation of cytochrome b reported here for V. inaequalis describes the first example of a mutation in filamentous ascomycetes and is part of an assessment of resistance risks inherent to strobilurin fungicides. |
| Databáze: | OpenAIRE |
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