The rapid spread of insecticide resistance in malaria vectors populations is reducing the effectiveness of control tools. Elucidating the molecular basis of this resistance is vital to improve the control of these vectors. However, despite playing a major role, metabolic resistance remains poorly characterised. Here, we analysed the genetic variation of two cytochrome P450 genes, CYP6M2 and CYP6P4, associated with pyrethroid resistance using genes sequences analysis on field strains of Anopheles coluzzii and Anopheles gambiae, to detect a potential resistance signature.
This study, in addition to the detected pyrethroid resistance escalation, highlighted the involvement of kdr target site resistance mutation, nearly fixed (93%) in the An. coluzzii population from Ngousso and fixed in the An. gambiae population from Nkolondom (100%), associated to metabolic resistance with a recovery of susceptibility of 23.67% for An. coluzzii and 16% for An. gambiae after a pre-exposure to PBO, due to many P450 genes among which CYP6M2 and CYP6P4. For CYP6M2, the gene upstream region shows low diversity in highly-resistant and highly-susceptible, whereas the full-gene shows allelic-variation but without evidence of ongoing selection. For CYP6P4, the upstream region showed a diversity lower in highly-resistant than highly-susceptible of An. gambiae.
These results highlighted that CYP6P4-associated resistance is potentially driven by modification in upstream region. However, further work is needed to determine the real causative variants that will help design rapid detection tools.
Read the article : https://doi.org/10.3390/genes14010052
