Abstract: Objective To investigate the current resistance status of Aedes albopictus to pyrethroid insecticides at the molecular level through the voltage-gated sodium channel (VGSC) genes testing in three field populations of Ae. albopictus in Neijiang, Sichuan province, China.Methods From June to July in 2021, adult mosquitoes were collected by light trapping method in the Ae. albopictus breeding sites of three counties/cities/districts in Neijiang. For mosquitoes identified as Ae. albopictus, the genomic DNA was extracted to amplify VGSC gene fragment using PCR, followed by detection of mutation types and distribution frequencies at VGSC gene resistance-related loci (loci 1016, 1532, and 1534).Results A total of 107 Ae. albopictus mosquitoes were collected and sequenced successfully. Twenty-eight (26.17%) mosquitoes were detected with the 1016G mutation, six (5.61%) with the 1532T mutation, and 100 (93.46%) with the 1534C/S mutations. The combination analysis of the three loci revealed that 76 (73.08%) mosquitoes had mutations at only one locus, and 25 (24.04%) at two loci. There were two (1.92%) mosquitoes with the wild type at 1016 and mutations at both 1532 and 1534, 22 (21.15%) with the wild type at 1532 and mutations at both 1016 and 1534, and one (0.96%) with the wild type at 1534 and mutations at both 1532 and 1016. None had simultaneous mutations at all the three loci.Conclusions The three field Ae. albopictus populations in Neijiang had frequent pyrethroid target-site mutations, with a high frequency of resistance at locus 1534, where 1534S was the dominant resistance allele, suggesting that the use of pyrethroids should be reduced in chemical control to delay resistance and improve mosquito control.

Key words: Aedes albopictus, Mutation, Voltage-gated sodium channel

摘要： 目的 通过对四川省内江市3个白纹伊蚊野外群体电压门控钠离子通道（voltage-gated sodium channel,VGSC）基因检测分析,在分子水平上了解白纹伊蚊对拟除虫菊酯类杀虫剂的抗药性现状。方法 2021年6－7月,在内江市3个县（市、区）白纹伊蚊孳生地使用诱蚊灯法采集野外成蚊,鉴定为白纹伊蚊后,提取基因组DNA,扩增VGSC基因片段,检测VGSC基因抗药性相关位点（1016、1532和1534）的突变类型及其分布频率。结果 共收集并成功测序107只白纹伊蚊,检测到1016G突变的有28只,占26.17%,发生1532T突变的有6只,占5.61%,1534位点发生突变（1534C/S）的共100只,占93.46%。对1016、1532、1534位点组合分析发现,仅1个位点为突变型的个体为76个（73.08%）,2个位点为突变型的个体共25个（24.04%）,其中1016位点为野生型、1532和1534位点同时突变的个体为2个（1.92%）,1532位点为野生型、1016和1534位点同时突变的个体为22个（21.15%）,1534位点为野生型、1532和1016位点同时突变的个体共1个（0.96%）。本次现场未发现3个位点同时突变的个体。结论 内江市3个白纹伊蚊野外种群存在较高频率的拟除虫菊酯类杀虫剂靶标突变,其中1534位点抗性频率较高,1534S是优势抗性等位基因,提示在化学防治蚊虫时,宜减少拟除虫菊酯类杀虫剂的使用,以延缓抗药性的产生,提高蚊媒控制效果。

关键词: 白纹伊蚊, 突变, 电压门控钠离子通道