Propoxur resistance associated with insensitivity of acetylcholinesterase (AChE) in the housefly, Musca domestica (Diptera: Muscidae)

Abstract

Two unique housefly strains, PSS and N-PRS (near-isogenic line with the PSS), were used to clarify the mechanisms associated with propoxur resistance in the housefly, Musca domestica. The propoxurselected resistant (N-PRS) strain exhibited >1035-fold resistance to propoxur and 1.70-, 12.06-, 4.28-, 57.76-, and 57.54-fold cross-resistance to beta-cypermethrin, deltamethrin, bifenthrin, phoxim, and azamethiphos, respectively, compared to the susceptible (PSS) strain. We purified acetylcholinesterase (AChE) from the N-PRS and PSS strains using a procainamide affinity column and characterized the AChE. The sensitivity of AChE to propoxur based on the bimolecular rate constant (K i) was approximately 100-fold higher in the PSS strain compared to the N-PRS strain. The cDNA encoding Mdace from both the N-PRS strain and the PSS strain were cloned and sequenced using RT-PCR. The cDNA was 2073 nucleotides long and encoded a protein of 691 amino acids. A total of four single nucleotide polymorphisms (SNPs), I162M, V260L, G342A, and F407Y, were present in the region of the active site of AChE from the N-PRS strain. The transcription level and DNA copy number of Mdace were significantly higher in the resistant strain than in the susceptible strain. These results indicated that mutations combined with the up-regulation of Mdace might be essential in the housefly resistance to propoxur.

The overexpression and variant of CYP6G4 associated with propoxur resistance in the housefly, Musca domestica L.

“…Higher synergistic effects of PBO to propoxur in the N‐PRS were observed in our study, suggesting that the possibility of cytochrome P450‐based mechanism was associated with propoxur resistance. Nevertheless, the propoxur resistance in the N‐PRS could not be eliminated completely by PBO, which can be explained by the molecular target mutations and Mdace ‐mediated mechanism presented in the N‐PRS as previously described 7 …”

“…In a previous study, You et al . reported that the mutations and overexpression of Mdace were involved in the housefly propoxur resistance 7 . It has been identified there was an additional gene or genes other than one major factor involved in propoxur resistance 8 …”

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“…В нескольких районах Китая отмечены высокие значения ПР комнатной мухи к пропоксуру (154-1000), в то время как в некоторых районах она была чувствительна к этому инсектициду (Wang et al, 2019). Отселектированная в лабораторных условиях раса (N-PRS) проявила >1035× устойчивость к пропоксуру и 1.7-, 12.1-, 4.3-, 57.8-и 57.5-кратную перекрестную устойчивость к бета-циперметрину, дельтаметрину, бифентрину, фоксиму и азаметифосу, соответственно, по сравнению с чувствительной расой (PSS) (You et al, 2020).…”

“…Кроме того, уровень транскрипции и количество копий ДНК Mdace были значительно выше у устойчивой расы, чем у чувствительной. Таким образом, мутации в сочетании с повышенной экспрессией генов могут иметь важное значение для устойчивости комнатной мухи к пропоксуру (You et al, 2020).…”

Polymorphism and Distribution of Ace Gene Involved in the Resistance of Musca Domestica to Organophosphates in Guizhou Province of China

“…This in turn leaves the acetylcholine receptor permanently open, resulting in the death of the insect [10]. However, modi cation or mutation of the ace gene can change the structure of AChE, thereby reducing or eliminating the binding a nity of insecticides at the target-site and inducing the resistance to OPs and CBs[8, 12,13]. For house ies, there is only a single ace gene in the whole genome [14].…”