Prevalence characteristics of knockdown resistance gene of Aedes aegypti in Yunnan Province,China
Objective To investigate mutations in the voltage-gated sodium channel gene(VGSC)responsible for knockdown resistance(kdr)in Aedes aegypti and analyze the prevalence characteristics of the VGSC gene in the key areas of Ae.aegypti distribution in Yunnan Province,China.Methods Wild adult or larval Ae.aegypti samples were collected from 7 counties/cities(Yingjiang County,Ruili City,Zhenkang County,Gengma Dai and Va Autonomous County,Menghai County,Jinghong Municipality,and Mengla County)in Yunnan Province.The gene VGSC was amplified by direct sequencing to analyze the point mutation rate and the composition of combined mutations.The Chi-square test was used to compare the differences in the kdr mutation rate of VGSC gene between different loci and between different sexes of Aedes albopictus.Results The DNA was successfully extracted and VGSC gene were sequenced for a total of 561 Ae.aegypti mosquitoes(276 females,242 males,and 43 larvae)in 7 counties/cities.Four point mutations were found in the VGSC gene.S989P,V1016G,and F1534C mutations were present in every county/city.The S989P mutation rate ranged from 71.43%to 100%,with a mean of 92.51%(95%confidence interval[CI]:90.33%-94.70%).The V1016G mutation rate was 100%.The F1534C mutation rate was 55.81%-100%,with a mean of 85.38%(95%CI:82.45%-88.32%).The Y1527F mutation was first detected in Ruili Municipality,Gengma and Zhenkang County,and the mutation rate ranged from 0 to 35.45%,with a mean of 8.73%(95%CI:6.39%-11.08%).There were 4 types of co-occurring mutations:S989P+V1016G,V1016G+F1534C,S989P+V1016G+F1534C,and S989P+V1016G+ Y1527F+F1534C.Single point mutations were not found.There were no significant differences in the mutation rates of 989,1016,1527,and 1534 loci and the composition ratios of combined mutations in female and male mosquitoes in six counties/cities except Yingjiang County.Conclusions The kdr mutation in the VGSC gene of Ae.aegypti in Yunnan Province is mainly characterized by multiple-point joint mutations,and a new Y1527F mutation appears.Kdr mutations surveillance in Ae.aegypti should be carried out regularly to grasp the changes in its resistance to insecticide targets in time.
Aedes aegyptiVoltage-gated sodium channelKnockdown resistance mutationCombined mutationYunnan Province
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NSTL
万方数据
