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The Y137H mutation in the cytochrome P450 FgCYP51B protein confers reduced sensitivity to tebuconazole in Fusarium graminearum
Author(s) -
Qian Hengwei,
Du Juan,
Chi Mengyu,
Sun Xiaomei,
Liang Wenxing,
Huang Jinguang,
Li Baodu
Publication year - 2018
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.4837
Subject(s) - tebuconazole , biology , mutant , point mutation , fusarium , wild type , tec , fungicide , cytochrome p450 , gene , demethylation , biochemistry , genetics , botany , gene expression , enzyme , ionosphere , physics , astronomy , dna methylation
Abstract BACKGROUND Fusarium graminearum is the main pathogen of Fusarium head blight (FHB), a worldwide plant disease and one of the most significant wheat diseases in China. Demethylation inhibitor (DMI) fungicides, such as tebuconazole (TEC), are widely used to control FHB, but long‐term use leads to low efficacy against FHB. Earlier studies showed that DMI resistance is associated with the fungal sterol 14α‐demethylase (cytochrome P450 CYP51 ) gene, and that point mutations in the CYP51 gene are the primary mechanism of resistance to DMI fungicides. The aims of this study were to clarify the molecular mechanisms of resistance to TEC and identify the binding sites on the FgCYP51B protein. RESULTS Site‐directed mutagenesis was used to change the FgCYP51B gene of wild‐type strain PH‐1 from tyrosine to histidine at residue 137 (Y137H) to generate a mutant transformant, which was confirmed to be resistant to TEC compared with the parental strains. A three‐dimensional FgCYP51B model was constructed, and molecular docking simulation studies were conducted to identify the optimum binding mode with TEC. The wild‐type FgCYP51B protein displayed stronger affinity to TEC than that of the mutated FgCYP51B in the molecular docking analysis. CONCLUSION These results indicate that a Tyr137 amino acid mutation in the cytochrome P450 FgCYP51B could lead to resistance to TEC and that Y137 forms part of the tebuconazole‐binding pocket. © 2017 Society of Chemical Industry