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Genetic analysis of resistance to fenpropimorph in Aspergillus niger
A J Engels1, E F Holub, K Swart
1Department of Phytopathology, Wageningen Agricultural University, Binnenhaven 9, 6709 PD Wageningen, The Netherlands.
Abstract:
Resistance to the morpholine-fungicide fenpropimorph was studied in Aspergillus niger and A. nidulans. Mass selection of conidia of A. nidulans on agar amended with the fungicide at different concentrations did not yield of resistant mutants, even after UV-treatment of the conidia. In contrast, similar experiments with A. niger generated many fenpropimorph-resistant mutants. The mutants displayed cross-resistance to fenpropidin and generally showed wild-type sensitivity to the unrelated toxicants fenarimol and cycloheximide. Genetic analysis of fenpropimorph resistance in A. niger was carried out by means of the parasexual cycle. In the mutants tested, two genes located on linkage group II were involved in fenpropimorph resistance. Dominance tests showed that resistance to fenpropimorph in A. niger is recessive.
Insights
Fenpropimorph fungicide resistance developed in Aspergillus niger but not A. nidulans. Genetic analysis revealed two recessive genes on linkage group II confer resistance in A. niger.
Area of Science:
- Agricultural Science
- Mycology
- Genetics
Background:
- Fungal resistance to fungicides poses a significant challenge in agriculture.
- Morpholine fungicides, like fenpropimorph, are crucial for crop protection.
- Understanding the genetic basis of fungicide resistance is vital for sustainable agriculture.
Purpose of the Study:
- To investigate the development of fenpropimorph resistance in Aspergillus species.
- To identify the genetic mechanisms underlying fenpropimorph resistance in Aspergillus niger.
Main Methods:
- Comparative resistance screening of Aspergillus niger and Aspergillus nidulans to fenpropimorph.
- Induction of mutations using UV-treatment.
- Genetic analysis utilizing the parasexual cycle in Aspergillus niger.
- Cross-resistance testing with related and unrelated toxicants.
Main Results:
- Aspergillus niger readily developed fenpropimorph resistance, unlike Aspergillus nidulans.
- Mutants exhibited cross-resistance to fenpropidin but remained sensitive to fenarimol and cycloheximide.
- Genetic mapping identified two genes on linkage group II associated with fenpropimorph resistance.
- Resistance was determined to be recessive in Aspergillus niger.
Conclusions:
- Aspergillus niger is a suitable model for studying fungicide resistance mechanisms.
- The identified genes provide targets for understanding and managing fenpropimorph resistance.
- Recessive resistance suggests specific genetic pathways involved in fungicide detoxification or target modification.