Knockdown resistance and acetylcholinesterase genes sequence analysis in Musca domestica from Iran

Background: Housefly, Musca domestica L., is a very important mechanical vector of pathogens. Continuous exposure to different insecticides has led to resistance in houseflies. Resistance is associated with a number of mutations in the voltage-gated sodium channel gene (vgsc) and the acetylcholinesterase (Ace) gene.Objectives: We investigate the sequence of both genes to find resistance-related mutations in the housefly.Materials and Methods:Houseflies were collected from Azerbaijan-Gharbi, Guilan and Ardebil provinces in Northwestern Iran. The DNA was extracted using YTA kit, kdr and Ace fragments amplified using specific primers. Sequences were analyzed using bioinformatics software.Results:Analysis of kdr gene sequences showed two amino acid substitutions at N967Y (9.5%) and L1014H (4.7%) positions. In acetylcholinesterase sequences, nucleotide polymorphisms (SNPs) in exon I lead to amino acid substitutions in V260L, G342A, G342V positions. In exon II region, T/A mutation was not silent and lead to F407Y substitutions in 80% of the samples. Genotyping results showed that more than 85% of specimens have at least one of these mutations. The Iranian housefly population was composed of five insensitive and a sensitive allele.Conclusion:The emergence of multiple alleles in field population might due to the application of different pesticides/insecticides during long periods on the Iranian population. Monitoring the frequency of resistance mutations will be helpful in avoiding overuse of insecticides and better resistance management. Development of an effective control strategy for such populations will be difficult

Keywords:

housefly , acetylcholinesterase , voltage-sensitive sodium channel polymorphism , novel mutation