海口市白纹伊蚊对菊酯类杀虫剂的抗药性及击倒抗性基因突变分析

目的 了解海口市白纹伊蚊对溴氰菊酯和氯菊酯的抗药性,并检测其击倒抗性(kdr)基因突变型,阐明抗性表型与kdr基因突变的关系。 方法 在海口新埠岛、龙塘镇、石山镇、白沙门和花卉市场采集白纹伊蚊幼虫,应用浸渍法测定其对溴氰菊酯和氯菊酯杀虫剂的敏感性,以抗性倍数确定抗性级别。对应生物测定的样品扩增和分析白纹伊蚊的kdr基因部分片段,采用χ²检验比较抗性表型与kdr突变基因型的差异性。 结果 海口白纹伊蚊花卉市场和白沙门群体对溴氰菊酯和氯菊酯均产生抗性,花卉市场群体对溴氰菊酯的抗性倍数高达436.36,为高度抗性。龙塘镇和石山镇群体对氯菊酯均为敏感,对溴氰菊酯的抗性为低度(9.09)或中度(18.18)。新埠岛群体对溴氰菊酯和氯菊酯均为敏感。在对应检测的317只白纹伊蚊的kdr基因中,发现1 534位点存在点突变,检测到2种突变等位基因(TGC/C、TCC/S)。5种基因型和频率分别为野生型TTC/TTC(62.15%)、野生/突变型杂合子TTC/TGC(0.63%)和TTC/TCC(16.09%)、突变型纯合子TCC/TCC(20.82%)以及突变型杂合子TGC/TCC(0.32%)。χ²检验结果显示,接触菊酯类杀虫剂后敏感表型与抗性表型个体中,kdr基因型间的差异有统计学意义(P <0.05),在抗性表型群体中的kdr突变型基因型的频率(42.94%)大于敏感表型个体(31.97%)。 结论 海口市白纹伊蚊多个群体对溴氰菊酯和氯菊酯同时存在抗性,抗性表型与kdr突变基因型密切相关。本研究首次记录了kdr新的等位基因TCC/S。

Resistance to pyrethroid insecticides and analysis of knockdown resistance (kdr) gene mutations in Aedes albopictus from Haikou City

Objective To investigate the resistance to deltamethrin and permethrin in Aedes albopictus in Haikou City, and to detect the knockdown resistance (kdr) mutants of A. albopictus, elucidating the association of resistant phenotype with kdr mutation. Methods The A. albopictus samples were collected from Xinfu Island, Longtang Town, Shishan Town, Baishamen Park, and the flower market in Haikou City. Their susceptibility to deltamethrin and permethrin was tested by larval bioassay. The resistance level was determined by the R/S ratio. The kdr gene was amplified and analyzed, and the relationship between the resistant phenotype and kdr mutation was determined by Chi-square test. Results The A. albopictus samples from the flower market and Baishamen Park showed resistance to deltamethrin and permethrin, of which the flower market population had an R/S ratio of up to 436.36, indicating a high level of resistance. The A. albopictus samples from Longtang Town and Shishan Town were sensitive to permethrin, but had low (R/S ratio, 9.09) and moderate (18.18) degrees of resistance to deltamethrin, respectively. The Xinfu Island population was sensitive to both deltamethrin and permethrin. The codon 1 534 kdr was detected point mutations among 317 A. albopictus samples, with two mutant alleles, TGC/C and TCC/S. The five genotypes were wild-type TTC/TTC (frequency, 62.15%), wild/mutant heterozygous TTC/TGC (0.63%) and TTC/TCC (16.09%), homozygous mutant TCC/TCC (20.82%), and mutant heterozygous TGC/TCC (0.32%). Chi-square test revealed significant differences in the frequency of kdr mutant genotype between A. albopictu sensitive to the insecticides (31.97%) and those resistant to the insecticides (42.94%), P <0.05. Conclusion Some A. albopictus populations in Haikou City have developed resistance to both deltamethrin and permethrin. The resistant phenotype and kdr mutant genotype are closely associated. This study has also discovered for the first time the novel TCC/S point mutation of kdr.