title: A PCR-based method to characterise and identify benzimidazole resistance in Helminthosporium solani.
abstract: Control of Helminthosporium solani, the cause of silver scurf in potato tubers, has been impaired by selection of benzimidazole-resistant strains as a result of repeated use of the fungicide thiabendazole. Identification of thiabendazole-resistant strains of H. solani by conventional techniques takes several weeks. Primers designed from conserved regions of the fungal beta-tubulin gene were used to PCR amplify and sequence a portion of the gene. A point mutation was detected at codon 198 in thiabendazole-resistant isolates causing a change in the amino acid sequence from glutamic acid to alanine or glutamine. Species-specific PCR primers designed to amplify this region were used in conjunction with a restriction endonuclease to cause cleavage in sensitive isolates only and thus provide a rapid diagnostic test to differentiate field isolates.
authors.affiliation: Department of Applied Plant Science, Queen's University of Belfast, UK. G.J.MCKAY@QUB.AC.UK
authors.forename: G J
authors.initials: GJ
authors.lastname: McKay
authors.forename: L R
authors.initials: LR
authors.lastname: Cooke
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001562:Benzimidazoles / Q000494:pharmacology*; D004252:DNA Mutational Analysis; D004271:DNA, Fungal / Q000235:genetics*; D004352:Drug Resistance, Microbial / Q000235:genetics; D005659:Fungicides, Industrial / Q000494:pharmacology*; D005800:Genes, Fungal / Q000235:genetics; D006375:Helminthosporium / Q000187:drug effects*; D008969:Molecular Sequence Data; D017354:Point Mutation / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D014404:Tubulin / Q000235:genetics
chemical_list: D001562:Benzimidazoles; D004271:DNA, Fungal; D005659:Fungicides, Industrial; D014404:Tubulin; C031000:benzimidazole