At least two origins of fungicide resistance in grapevine downy mildew Populations
Journal
Applied and Environmental Microbiology
Journal Volume
73
Journal Issue
16
Pages
5162-5172
Date Issued
2007
Author(s)
Delmotte, Francois
Richard-Cervera, Sylvie
Douence, Lisette
Greif, Charles
Corio-Costet, Marie-France
URI
Abstract
Quinone outside inhibiting (QoI) fungicides represent one of the most widely used groups of fungicides used to control agriculturally important fungal pathogens. They inhibit the cytochrome bc1 complex of mitochondrial respiration. Soon after their introduction onto the market in 1996, QoI fungicide-resistant isolates were detected in field plant pathogen populations of a large range of species. However, there is still little understanding of the processes driving the development of QoI fungicide resistance in plant pathogens. In particular, it is unknown whether fungicide resistance occurs independently in isolated populations or if it appears once and then spreads globally by migration. Here, we provide the first case study of the evolutionary processes that lead to the emergence of QoI fungicide resistance in the plant pathogen Plasmopara viticola. Sequence analysis of the complete cytochrome b gene showed that all resistant isolates carried a mutation resulting in the replacement of glycine by alanine at codon 143 (G143A). Phylogenetic analysis of a large mitochondrial DNA fragment including the cytochrome b gene (2,281 bp) across a wide range of European P. viticola isolates allowed the detection of four major haplotypes belonging to two distinct clades, each of which contains a different QoI fungicide resistance allele. This is the first demonstration that a selected substitution conferring resistance to a fungicide has occurred several times in a plant-pathogen system. Finally, a high population structure was found when the frequency of QoI fungicide resistance haplotypes was assessed in 17 French vineyards, indicating that pathogen populations might be under strong directional selection for local adaptation to fungicide pressure. Copyright © 2007, American Society for Microbiology. All Rights Reserved.
Subjects
Fruits; Pathogens; Plants (botany); Proteins; Fungicide resistance; Plant pathogens; Fungicides; fungicide; mitochondrial DNA; ubiquinol cytochrome c reductase; adaptation; evolution; fungicide; fungus; mitochondrial DNA; mutation; pesticide resistance; phylogeny; population structure; selection; vineyard; amino acid substitution; article; downy mildew; fungal gene; fungicidal activity; fungicide resistance; grape; haplotype; nonhuman; nucleotide sequence; phylogenetic tree; Plasmopara viticola; Alleles; Cytochromes b; DNA, Mitochondrial; Drug Resistance, Fungal; Electron Transport Complex III; Evolution, Molecular; Fungicides, Industrial; Genes, Fungal; Haplotypes; Methacrylates; Microbial Sensitivity Tests; Molecular Sequence Data; Oxazoles; Peronospora; Phylogeny; Polymorphism, Single Nucleotide; Sequence Analysis, DNA; Vitis; Eurasia; Europe; France; Western Europe; Peronosporaceae; Plasmopara viticola; Vitis
Type
journal article