title: Monitoring of Venturia inaequalis harbouring the QoI resistance G143A mutation in French orchards as revealed by PCR assays.
abstract: BACKGROUND
  Genetic resistance to QoI fungicides may account for recent failures to control Venturia inaequalis (Cooke) Winter in French orchards. Two PCR-based assays were developed to detect the G143A point mutation in the fungal mitochondrial cytochrome b gene. The mutation is known to confer a high level of resistance to QoI fungicides. Occurrence of the G143A mutation in French field isolates collected from 2004 to 2007 was monitored.
  
  
  RESULTS
  The QoI-resistant cytochrome b allele was specifically detected either following the cleavage of the amplified marker by a restriction endonuclease (CAPS assay) or its amplification using an allele-specific PCR primer. Using either method, the G143A mutation was found in 42% of the 291 field samples originating from French orchards in which apple scab proved difficult to be controlled. Monitoring of the G143A mutation in orchards located in 15 French administrative regions indicated that the mutation was detected at least once in nine of the regions, and its presence ranged from 33% to 64% of the orchards analysed in 2004 and in 2007 respectively.
  
  
  CONCLUSIONS
  The PCR-based methods developed in this study efficiently reveal the presence of the G143A mutation in French V. inaequalis field populations.
authors.affiliation: DRAF-SRPV Rhône Alpes, Cité Administrative de la Part Dieu, Lyon, France.
authors.forename: Séverine
authors.initials: S
authors.lastname: Fontaine
authors.forename: Florent
authors.initials: F
authors.lastname: Remuson
authors.forename: Laurence
authors.initials: L
authors.lastname: Fraissinet-Tachet
authors.forename: Annie
authors.initials: A
authors.lastname: Micoud
authors.forename: Roland
authors.initials: R
authors.lastname: Marmeisse
authors.forename: Delphine
authors.initials: D
authors.lastname: Melayah
mesh_terms: D000483:Alleles; D001483:Base Sequence; D045303:Cytochromes b / Q000235:genetics; D025141:Drug Resistance, Fungal; D005602:France; D005658:Fungi / Q000187:drug effects* / Q000235:genetics*; D005659:Fungicides, Industrial / Q000494:pharmacology*; D027845:Malus / Q000382:microbiology*; D009154:Mutation; D016133:Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D005659:Fungicides, Industrial; D045303:Cytochromes b