title: Molecular mechanism of resistance of Fusarium fujikuroi to benzimidazole fungicides.
abstract: Although carbendazim (MBC) and other benzimidazole fungicides have effectively controlled bakanae disease of rice (which is caused by Fusarium fujikuroi, F. proliferatum, and F. verticillioides) in the past, MBC resistance has become common. Previous research has shown that MBC resistance results from a mutation in the β1 -tubulin (β1 tub) gene in F. verticillioides. However, MBC resistance in F. fujikuroi, a predominant species in China, does not result from a mutation in the β1 tub. The molecular mechanism of F. fujikuroi resistance against benzimidazole fungicides is poorly understood. In this study, we determined that although β1 tub and β2 -tubulin (β2 tub) in F. fujikuroi have high homology with β1 tub and β2 tub in F. verticillioides, MBC resistance in F. fujikuroi results from mutations in β2 tub [GAG(Glu)→GTG(Val) at codon 198, TTC(Phe)→TAC(Tyr) at codon 200, and GGC(Gly)→GGT(Gly) at codon 235] but not in β1 tub. Δβ2 tub (β2 tub deletion) mutants were highly sensitive to MBC, produced fewer conidia and were less virulent than parental strains. Complementation of the Δβ2 tub mutants with a copy of the whole β2 tub locus from their parental strains restored the level of MBC resistance (or sensitivity) to that of the parental strain.
authors.affiliation: College of Plant Protection, Nanjing Agricultural University, Nanjing, China; Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing, Jiangsu Province, China; Key Laboratory of Pesticides, Nanjing Agricultural University, Nanjing, Jiangsu Province, China.
authors.forename: Zihao
authors.initials: Z
authors.lastname: Chen
authors.forename: Tao
authors.initials: T
authors.lastname: Gao
authors.forename: Shuping
authors.initials: S
authors.lastname: Liang
authors.forename: Kexue
authors.initials: K
authors.lastname: Liu
authors.forename: Mingguo
authors.initials: M
authors.lastname: Zhou
authors.forename: Changjun
authors.initials: C
authors.lastname: Chen
mesh_terms: D001562:Benzimidazoles / Q000494:pharmacology*; D002219:Carbamates / Q000494:pharmacology; D025141:Drug Resistance, Fungal / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics; D005659:Fungicides, Industrial / Q000494:pharmacology*; D060585:Fusariosis / Q000382:microbiology; D005670:Fusarium / Q000187:drug effects* / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D014404:Tubulin / Q000235:genetics
chemical_list: D001562:Benzimidazoles; D002219:Carbamates; D005656:Fungal Proteins; D005659:Fungicides, Industrial; D014404:Tubulin; C031000:benzimidazole; C006698:carbendazim
keywords: Fusarium fujikuroi; carbendazim resistance; molecular resistance mechanism; β1-tubulin gene