Department of Entomology, Comstock Hall, Cornell University, Ithaca, NY 14853, USA.
Department of Entomology, University of Minnesota, St. Paul, MN 55108, USA.
Pestic Biochem Physiol. 2023 Aug;194:105497. doi: 10.1016/j.pestbp.2023.105497. Epub 2023 Jun 12.
House flies (Musca domestica L) are nuisances and vectors of pathogens between and among humans and livestock. Population suppression has been accomplished for decades with pyrethroids and acetylcholinesterase (AChE) inhibitors, but recurrent selection has led to increased frequency of alleles conferring resistance to those two classes of active ingredients (Geden et al., 2021). A common mechanism of resistance to both classes involves an altered target site (mutations in Voltage gated sodium channel (Vgsc) for pyrethroids or in Ace for AChE inhibitors). As part of ongoing efforts to understand the origin, spread and evolution of insecticide resistance alleles in house fly populations, we sampled flies in 11 different US states, sequenced, and then estimated frequencies of the Vgsc and Ace alleles. There was substantial variation in frequencies of the four common knockdown resistance alleles (kdr (L1014F), kdr-his (L1014H), super-kdr (M918T + L10414F) and 1B (T929I + L1014F) across the sampled states. The kdr allele was found in all 11 states and was the most common allele in four of them. The super-kdr allele was detected in only six collections, with the highest frequencies found in the north, northeast and central United States. The kdr-his allele was the most common allele in PA, NC, TN and TX. In addition, a novel super-kdr-like mutation in mutually exclusive exon 17a was found. The overall frequencies of the different Ace alleles, which we name based on the amino acid present at the mutation sites (V260L, A316S, G342A/V and F407Y), varied considerably between states. Five Ace alleles were identified: VAGF, VAVY, VAGY, VAAY and VSAY. Generally, the VSAY allele was the most common in the populations sampled. The susceptible allele (VAGF) was found in all populations, ranging in frequency from 3% (KS) to 41% (GA). Comparisons of these resistance allele frequencies with those previously found suggests a dynamic interaction between the different alleles, in terms of levels of resistance they confer and likely fitness costs they impose in the absence of insecticides.
家蝇（Musca domestica L）不仅是人类和家畜之间病原体的传播媒介，而且还会造成滋扰。几十年来，一直使用拟除虫菊酯和乙酰胆碱酯酶 (AChE) 抑制剂来控制家蝇的数量，但反复选择导致了对这两类活性成分（Geden 等人，2021 年）具有抗性的等位基因的频率增加。对这两类物质的共同抗性机制涉及靶标位点的改变（拟除虫菊酯的电压门控钠离子通道 (Vgsc) 或 AChE 抑制剂的 Ace 发生突变）。作为了解家蝇种群中杀虫剂抗性等位基因的起源、传播和进化的持续努力的一部分，我们在 11 个不同的美国州采样了苍蝇，对其进行了测序，并估计了 Vgsc 和 Ace 等位基因的频率。在所采样的州中，四个常见击倒抗性等位基因（kdr (L1014F)、kdr-his (L1014H)、超级 kdr (M918T + L10414F) 和 1B (T929I + L1014F)）的频率存在显著差异。kdr 等位基因在 11 个州均有发现，在其中 4 个州最为常见。超级 kdr 等位基因仅在 6 个采集点中被检测到，在北美、东北和中部美国的频率最高。kdr-his 等位基因在宾夕法尼亚州、北卡罗来纳州、田纳西州和得克萨斯州最为常见。此外，还发现了一个在互斥外显子 17a 中新的超级 kdr 样突变。不同 Ace 等位基因的总体频率（我们根据突变位点存在的氨基酸命名（V260L、A316S、G342A/V 和 F407Y））在各州之间差异很大。共鉴定出 5 个 Ace 等位基因：VAGF、VAVY、VAGY、VAAY 和 VSAY。通常，VSAY 等位基因在采样的种群中最为常见。在所有种群中都发现了敏感等位基因（VAGF），其频率从 3%（KS）到 41%（GA）不等。与之前发现的抗性等位基因频率的比较表明，在没有杀虫剂的情况下，不同等位基因之间存在着动态的相互作用，包括它们赋予的抗性水平和可能的适应成本。
