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Dose-dependent genetic resistance to azole fungicides found in the apple scab pathogen

Heaven, Thomas, Armitage, Andrew D., Xu, Xiang-Ming, Goddard, Matthew, Cockerton, Helen M. (2023) Dose-dependent genetic resistance to azole fungicides found in the apple scab pathogen. Journal of Fungi, 9 (12). Article Number 1136. ISSN 2309-608X. (doi:10.3390/jof9121136) (KAR id:104141)


The evolution of azole resistance in fungal pathogens presents a major challenge in both crop production and human health. Apple orchards across the world are faced with the emergence of azole fungicide resistance in the apple scab pathogen Venturia inaequalis. Target site point mutations observed in this fungus to date cannot fully explain the reduction in sensitivity to azole fungicides. Here, polygenic resistance to tebuconazole was studied across a population of V. inaequalis. Genotyping by sequencing allowed Quantitative Trait Loci (QTLs) mapping to identify the genetic components controlling this fungicide resistance. Dose-dependent genetic resistance was identified, with distinct genetic components contributing to fungicide resistance at different exposure levels. A QTL within linkage group seven explained 65% of the variation in the effective dose required to reduce growth by 50% (ED50). This locus was also involved in resistance at lower fungicide doses (ED10). A second QTL in linkage group one was associated with dose-dependent resistance, explaining 34% of variation at low fungicide doses (ED10), but did not contribute to resistance at higher doses (ED50 and ED90). Within QTL regions, non-synonymous mutations were observed in several ATP-Binding Cassette and Major Facilitator SuperFamily transporter genes. These findings provide insight into the mechanisms of fungicide resistance that have evolved in horticultural pathogens. Identification of resistance gene candidates supports the development of molecular diagnostics to inform management practices.

Item Type: Article
DOI/Identification number: 10.3390/jof9121136
Additional information: For the purpose of open access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission.
Uncontrolled keywords: quantitative trait loci (QTLs); plant pathogen; biotroph; linkage map; genotyping by sequencing; single nucleotide polymorphism (SNP); genome; dose response; polygenic; tebuconazole
Subjects: Q Science
Q Science > QH Natural history > QH301 Biology
Q Science > QH Natural history > QH426 Genetics
Q Science > QK Botany
Divisions: Divisions > Division of Natural Sciences > Biosciences
Funders: Biotechnology and Biological Sciences Research Council (
Depositing User: Helen Cockerton
Date Deposited: 30 Nov 2023 17:19 UTC
Last Modified: 29 Feb 2024 14:49 UTC
Resource URI: (The current URI for this page, for reference purposes)

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