Insecticide-based vector control measures are extensively used in the fight against malaria. Unfortunately, insecticides are in danger of losing their potency due to the development of resistance in vector species populations. The worst-case scenario is when a single resistance mechanism confers resistance to many insecticide classes, thereby hindering resistance management. Therefore, applying appropriate insecticide-based interventions depends critically on understanding the different ways by which mosquitoes become resistant. We performed gene expression profiling (RNAseq) and whole genome sequencing (PoolSeq) of multiple resistant An. funestus collected from Ghana, Uganda, Malawi, laboratory-resistant (FUMOZ), and susceptible (FANG) strains. We found overexpression of metabolic cytochrome P450s genes in Malawi (CYP6P9a/b gene) and in Ghana (CYP6P4a/b) and also detected signatures of a substantial selection of some regions of the genome around these genes. Furthermore, in vitro expression of CYP6P9a/b P450s showed metabolic activities towards carbamates, and transgenic flies overexpressing resistant alleles of both genes were significantly more resistant to carbamates. Moreover, phenotype/genotype association studies revealed a strong correlation between carbamate resistance and CYP6P9a/b-resistant genotypes. This study demonstrated that P450-based pyrethroid resistance also confers resistance to carbamate insecticides.
Read more : https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1010678#
