Pest Management Science (2018) 74, 1265-1271

Mohammed Esmail Abdalla Elzaki, Mohammad Asaduzzaman Miah, Yingchuan Peng, Haomiao Zhang, Ling Jiang, Min Wu and Zhaojun Han (2018)
Deltamethrin is metabolized by CYP6FU1, a cytochrome P450 associated with pyrethroid resistance, in Laodelphax striatellus
Pest Management Science 74 (6), 1265-1271
Abstract:
Background
Cytochrome P450s (CYPs) are known to play a major role in metabolizing a wide range compounds. CYP6FU1 has been found to be over-expressed in a deltamethrin-resistant strain of Laodelphax striatellus. This study was conducted to express CYP6FU1 in Sf9 cells as a recombinant protein, to confirm its ability to degrade deltamethrin, chlorpyrifos, imidacloprid and traditional P450 probing substrates.
Results
Carbon monoxide difference spectrum analysis indicated that the intact CYP6FU1 protein was expressed in insect Sf9 cells. Catalytic activity tests with four traditional P450 probing substrates revealed that the expressed CYP6FU1 preferentially metabolized p-nitroanisole and ethoxyresorufin, but not ethoxycoumarin and luciferin-HEGE. The enzyme kinetic parameters were tested using p-nitroanisole. The michaelis constant (K_m) and catalytic constant (K_cat) values were 17.51 ± 4.29 µm and 0.218 ± 0.001 pmol min^-1 mg^-1 protein, respectively. Furthermore, CYP6FU1 activity for degradation of insecticides was tested by measuring substrate depletion and metabolite formation. The chromatogram analysis showed obvious nicotinamide-adenine dinucleotide phosphate (NADPH)-dependent depletion of deltamethrin, and formation of the unknown metabolite. Mass spectra and the molecular docking model showed that the metabolite was 4-hydroxy-deltamethrin. However, the recombinant CYP6FU1 could not metabolize imidacloprid and chlorpyrifos.
Conclusion
These results confirmed that the over-expressed CYP6FU1 contributes to deltamethrin resistance in L. striatellus, and p-nitroanisole might be a potential diagnostic probe for deltamethrin metabolic resistance detection and monitoring.
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Link to article at publishers website
Database assignments for author(s): Zhaojun Han

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Laodelphax striatellus