海口市2018年白纹伊蚊击倒抗性基因型分布研究

Genotypes of knockdown resistance gene and their distribution in Aedes albopictus in Haikou, China, in 2018

目的了解海南省海口市登革热媒介白纹伊蚊的击倒抗性基因(kdr)在不同区域的基因型及其分布特点,并分析其抗药性产生的影响因素,为白纹伊蚊化学防控提供依据。方法 2018年6-7月在海口市东、南、西、北、中5个方位,采集白纹伊蚊幼虫及蛹,饲养至成蚊,经形态学方法鉴定后,用无水乙醇溶液浸泡,并于-20℃冻存备用。提取单只蚊虫的DNA,PCR扩增神经细胞膜上电压门控钠离子通道(VGSC)基因部分片段,测序后分析kdr基因突变情况。结果对海口市不同方位采集的94只白纹伊蚊的检测结果显示,其kdr基因F1534位点存在突变。1534位点共有4种等位基因,即野生型TTC/F(113/60.11%),突变型TCC/S(66/35.11%)、TCG/S(1/0.53%)和TGC/C(8/4.26%);有6种基因型,分别为野生型纯合子F/F(39/41.49%),野生/突变型杂合子F/S(33/35.11%)、F/C(2/2.13%),突变型纯合子S/S(15/15.96%)、C/C(1/1.06%)和突变型杂合子S/C(4/4.26%)。各种群之间基因型比例各不相同。结论海口市kdr基因突变率较高,应进一步监测当地蚊虫抗药性,合理使用杀虫剂。

Objective To investigate the mutations in the knockdown resistance(kdr) gene of dengue vector Aedes albopictus in Haikou, China, as well as genotypes and their distribution in different areas, to analyze the influencing factors on insecticide resistance for scientific control of Ae. albopictus. Methods In June and July, 2018, the larvae and pupae of Ae.albopictus were collected from the urban and suburb areas of Haikou and reared to adults. The collected individuals were identified by morphology and were cryopreserved at -20 ℃ with anhydrous ethanol. DNA was extracted from a single mosquito, partial fragments of the voltage-gated sodium channel gene on nerve cell membrane were amplified by PCR, and sequencing was performed to analyze the mutations in the kdr gene. Results In the 94 Ae. albopictus mosquitoes in the east, south, west, north, and middle of Haikou, mutation was detected at the F1534 locus of the kdr gene. There were four alleles at the 1534 locus, namely, wild-type TTC/F(113/60.11%), mutant TCC/S(66/35.11%), mutant TCG/S(1/0.53%),and mutant TGC/C(8/4.26%);there were six genotypes, i.e., homozygous wild-type F/F(39/41.49%), wild/mutant heterozygote F/S(33/35.11%) and F/C(2/2.13%), homozygous mutant S/S(15/15.96%) and C/C(1/1.06%), and mutant heterozygote S/C(4/4.26%). The proportions of genotypes varied between populations. Conclusion The kdr mutation rate is high in Ae. albopictus in Haikou. Local mosquito resistance should be further monitored, so that insecticides are used appropriately.