福建省福州市和莆田市2020年白纹伊蚊击倒抗性基因突变分析

Knockdown resistance gene mutations of Aedes albopictus from Fuzhou and Putian,Fujian, 2020

目的了解福州市和莆田市登革热伊蚊监测点白纹伊蚊击倒抗性基因的突变情况。方法 2020年5—6月在福州市(晋安区、永泰县)和莆田市(涵江区、仙游县)采集白纹伊蚊幼虫,饲养繁殖,使用成蚊接触筒法实验结束的F1代单只雌蚊样本,提取DNA,PCR扩增电压门控钠离子通道(VGSC)基因部分片段,测序分析击倒抗性(knockdown resistance, kdr)基因突变情况。结果福州市和莆田市共检测491只白纹伊蚊,其中VGSC基因第Ⅱ结构域及第Ⅲ结构域的I1532位点未发现突变位点,第Ⅲ结构域的F1534位点存在突变。F1534位点有4种等位基因,即野生型TTC/F(252,25.66%)、突变型TCC/S(722,73.52%)、TGC/C(3,0.31%)和CTC/L(5,0.51%);7种基因型,分别为野生型纯合子F/F(39,7.94%),野生/突变型杂合子F/C(1,0.20%)、F/S(172,35.03%)和F/L(1,0.20%),突变型杂合子S/C(2,0.41%)和S/L(4,0.81%),突变型纯合子S/S(272,55.40%)。F1534位点突变等位基因TCC/S在4个种群中均有发现,且莆田市涵江区和仙游县的频率高于福州市晋安区和永泰县的频率。晋安区和永泰县F1534位点存在5种基因型,涵江区和仙游县则只有3种。野生/突变型杂合子F/S和突变型纯合子S/S在4个种群中均存在,野生型纯合子F/F只在涵江区中没有发现。晋安区和永泰县基因型以F/S为主,涵江区和仙游县以S/S为主。结论福州市和莆田市kdr基因突变频率高,以F1534S突变类型为主。提示应密切关注当地蚊虫抗性水平,减少拟除虫菊酯类杀虫剂的使用,科学合理地使用杀虫剂。

Objective To understand the mutations of knockdown resistance(kdr) gene of Aedes albopictus in dengue fever surveillance sites in Fuzhou and Putian.Methods From May to June in 2020, Aedes albopictus larvae were collected from Fuzhou(Jin’an District, Yongtai County) and Putian(Hanjiang District and Xianyou County), and then reared and reproduced in lab. DNA was extracted from each single female mosquito of F1 generation after the exposure tubes method on adults. Using PCR to amplify partial fragments of the voltage-gated sodium channel(VGSC) gene on the nerve cell membrane.The mutations in the kdr gene were analyzed by sequencing.Results A total of 491 Aedes albopictus were detected in Fuzhou and Putian, in which no mutation was found in domain Ⅱ or at I1532 locus in domain Ⅲ, but there were mutations at F1534 locus in domain Ⅲ of the VGSC gene. There were four alleles at the F1534 locus, namely wild-type TTC/F(252, 25.66%),mutant TCC/S(722, 73.52%), mutant TGC/C(3, 0.31%), and mutant CTC/L(5, 0.51%);seven genotypes, i.e., the wild-type homozygote F/F(39, 7.94%), wild/mutant heterozygote F/C(1, 0.20%), F/S(172, 35.03%) and F/L(1, 0.20%), mutant heterozygote S/C(2, 0.41%) and S/L(4, 0.81%), and mutant homozygote S/S(272, 55.40%). Mutant allele TCC/S at F1534 locus was found in all four populations and the frequencies in Hanjiang and Xianyou were higher than those in Jin’an and Yongtai. There were five genotypes at F1534 locus in Jin’an and Yongtai, but only three genotypes in Hanjiang and Xianyou.Wild/mutant heterozygote F/S and mutant homozygote S/S were found in all four populations, but wild-type homozygote F/F was not found in Hanjiang. The main genotype in Jin’an and Yongtai was F/S, while that in Hanjiang and Xianyou was S/S.Conclusion The kdr gene mutation rate is high in Fuzhou and Putian and F1534 S is the main mutation type. This suggests that we should pay close attention to the resistance level of local mosquitos, reduce the use of pyrethroid insecticides, and use insecticides scientifically and rationally.