The cytochrome P450 CYP325A is a major driver of pyrethroid resistance in the major malaria vector Anopheles funestus in Central Africa

Amelie N R Wamba, Sulaiman S Ibrahim, Michael O Kusimo, Abdullahi Muhammad, Leon M J Mugenzi, Helen Irving, Murielle J Wondji, Jack Hearn, Jude D Bigoga, Charles S Wondji

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

The overexpression and overactivity of key cytochrome P450s (CYP450) genes are major drivers of metabolic resistance to insecticides in African malaria vectors such as Anopheles funestus s.s. Previous RNAseq-based transcription analyses revealed elevated expression of CYP325A specific to Central African populations but its role in conferring resistance has not previously been demonstrated. In this study, RT-qPCR consistently confirmed that CYP325A is highly over-expressed in pyrethroid-resistant An. funestus from Cameroon, compared with a control strain and insecticide-unexposed mosquitoes. A synergist bioassay with PBO significantly recovered susceptibility for permethrin and deltamethrin indicating P450-based metabolic resistance. Analyses of the coding sequence of CYP325A Africa-wide detected high-levels of polymorphism, but with no predominant alleles selected by pyrethroid resistance. Geographical amino acid changes were detected notably in Cameroon. In silico homology modelling and molecular docking simulations predicted that CYP325A binds and metabolises type I and type II pyrethroids. Heterologous expression of recombinant CYP325A and metabolic assays confirmed that the most-common Cameroonian haplotype metabolises both type I and type II pyrethroids with depletion rate twice that the of the DR Congo haplotype. Analysis of the 1 kb putative promoter of CYP325A revealed reduced diversity in resistant mosquitoes compared to susceptible ones, suggesting a potential selective sweep in this region. The establishment of CYP325A as a pyrethroid resistance metabolising gene further explains pyrethroid resistance in Central African populations of An. funestus. Our work will facilitate future efforts to detect the causative resistance markers in the promoter region of CYP325A to design field applicable DNA-based diagnostic tools.

Original languageEnglish
Article number103647
JournalInsect Biochemistry and Molecular Biology
Volume138
DOIs
Publication statusPrint publication - Nov 2021
Externally publishedYes

Bibliographical note

Copyright © 2021. Published by Elsevier Ltd.

Keywords

  • Africa, Central
  • Animals
  • Anopheles/genetics
  • Computer Simulation
  • Cytochrome P-450 Enzyme System/genetics
  • Female
  • Insect Proteins/genetics
  • Insecticide Resistance/genetics
  • Insecticides/pharmacology
  • Malaria/transmission
  • Molecular Docking Simulation
  • Mosquito Vectors/genetics
  • Pyrethrins/pharmacology
  • Anopheles funestus
  • Metabolic resistance
  • Malaria
  • Pyrethroids
  • Cytochrome P450– CYP325A
  • Central Africa

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