Contreras-Perera Yamili, Ponce-Garcia Gustavo, Villanueva-Segura Karina, Lopez-Monroy Beatriz, Rodríguez-Sanchez Iram P, Lenhart Audrey, Manrique-Saide Pablo, Flores Adriana E
Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Cd, Universitaria, San Nicolas de los Garza, N.L., CP. 66455, Mexico.
Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA.
Parasit Vectors. 2020 May 6;13(1):224. doi: 10.1186/s13071-020-04093-3.
Insecticide resistance is a serious problem for vector control programmes worldwide. Resistance is commonly attributed to mutations at the insecticide's target site or increased activity of detoxification enzymes.
We determined the knockdown concentration (KC) and lethal concentration (LC) of deltamethrin in six natural populations of adult Aedes aegypti from southeastern Mexico. These populations were then selected over five generations using the LC from the preceding generation that underwent selection, and the heritability of deltamethrin resistance was quantified. For each generation, we also determined the frequency of the kdr alleles L410, I1016 and C1534, and the levels of activity of three enzyme families (α- and β-esterases, mixed-function oxidases and glutathione S-transferases (GST)) associated with insecticide detoxification.
There was an increase in KC and LC values in the subsequent generations of selection with deltamethrin (Fvs F). According to the resistance ratios (RRs), we detected increases in LC ranging from 1.5 to 5.6 times the values of the parental generation and in KC ranging from 1.3-3.8 times the values of the parental generation. Triple homozygous mutant individuals (tri-locus, LL/II/CC) were present in the parental generations and increased in frequency after selection. The frequency of L410 increased from 1.18-fold to 2.63-fold after selection with deltamethrin (Fvs F) in the populations analyzed; for I1016 an increase between 1.19-fold to 2.79-fold was observed, and C1534 was fixed in all populations after deltamethrin selection. Enzymatic activity varied significantly over the generations of selection. However, only α- esterase activity remained elevated in multiple populations after five generations of deltamethrin selection. We observed an increase in the mean activity levels of GSTs in two of the six populations analyzed.
The high levels of resistance and their association with high frequencies of kdr mutations (V410L, V1016I and F1534C) obtained through artificial selection, suggest an important role of these mutations in conferring resistance to deltamethrin. We highlight the need to implement strategies that involve the monitoring of kdr frequencies in insecticide resistance monitoring and management programmes.
杀虫剂抗性是全球病媒控制项目面临的一个严重问题。抗性通常归因于杀虫剂靶位点的突变或解毒酶活性的增加。
我们测定了来自墨西哥东南部的六个成年埃及伊蚊自然种群中溴氰菊酯的击倒浓度（KC）和致死浓度（LC）。然后，使用上一代经选择后的LC对这些种群进行了五代选择，并对溴氰菊酯抗性的遗传力进行了量化。对于每一代，我们还测定了击倒抗性（kdr）等位基因L410、I1016和C1534的频率，以及与杀虫剂解毒相关的三个酶家族（α-和β-酯酶、多功能氧化酶和谷胱甘肽S-转移酶（GST））的活性水平。
在溴氰菊酯选择的后续世代中，KC和LC值有所增加（F对F）。根据抗性比率（RRs），我们检测到LC增加幅度为亲代值的1.5至5.6倍，KC增加幅度为亲代值的1.3至3.8倍。三重纯合突变个体（三基因座，LL/II/CC）在亲代中存在，选择后频率增加。在分析的种群中，用溴氰菊酯选择后（F对F），L410的频率从1.18倍增加到2.63倍；对于I1016，观察到增加幅度在1.19倍至2.79倍之间，并且在溴氰菊酯选择后C1534在所有种群中固定。酶活性在选择世代间有显著变化。然而，在溴氰菊酯选择五代后，只有α-酯酶活性在多个种群中仍保持升高。我们在分析的六个种群中的两个种群中观察到GST平均活性水平增加。
通过人工选择获得的高水平抗性及其与高频率kdr突变（V410L、V1016I和F1534C）的关联，表明这些突变在赋予对溴氰菊酯抗性方面起着重要作用。我们强调在杀虫剂抗性监测和管理项目中实施涉及监测kdr频率的策略的必要性。
