title: Novel mutations in β-tubulin gene in Trichoderma harzianum mutants resistant to methyl benzimidazol-2-yl carbamate.
abstract: Twelve-low resistant (LR) mutants of Trichoderma harzianum with the capability of grow fast at 0.8 μg/mL methyl benzimidazol-2-yl carbamate (MBC) were obtained using UV mutagenesis. MR and HR mutants which could grow fast at 10 and 100 μg/mL MBC, respectively, were isolated by step-up selection protocols in which UV-treated mutants were induced and mycelial sector screening was made in plates with growth medium. Subsequently, β-tubulin genes of 14 mutants were cloned to describe-the molecular lesion likely to be responsible-for MBC resistance. Comparison of the β-tubulin sequences of the mutant and sensitive strains of T. harzianum revealed 2 new MBC-binding sites differed from those in other plant pathogens. A single mutation at-amino acid 168, having Phe (TTC) instead of Ser (TCC)', was demonstrated for the HR mutant; a double mutation in amino acid 13 resulting in the substitution of Gly (GGC) by Val (GTG) was observed in β-tubulin gene of MR mutant. On the other hand, no substitutions were identified in the β-tubulin gene and its 5'-flanking regions in 12 LR mutants of T. harzianum.
authors.forename: M
authors.initials: M
authors.lastname: Li
authors.forename: H Y
authors.initials: HY
authors.lastname: Zhang
authors.forename: B
authors.initials: B
authors.lastname: Liang
mesh_terms: D019943:Amino Acid Substitution; D001562:Benzimidazoles / Q000494:pharmacology*; D002219:Carbamates / Q000494:pharmacology*; D025141:Drug Resistance, Fungal / Q000187:drug effects / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D005659:Fungicides, Industrial / Q000494:pharmacology*; D005800:Genes, Fungal; D020125:Mutation, Missense; D014242:Trichoderma / Q000235:genetics* / Q000378:metabolism; D014404:Tubulin / Q000235:genetics*
chemical_list: D001562:Benzimidazoles; D002219:Carbamates; D005656:Fungal Proteins; D005659:Fungicides, Industrial; D014404:Tubulin; C006698:carbendazim