CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES ›› 2017, Vol. 35 ›› Issue (6): 536-540.

• ORGINAL ARTICLE • Previous Articles     Next Articles

Analysis of knowdown resistance gene mutation in Culex tritaeniorhynchus resistant to DDT and deltamethrin in Yunnan Province, China

Jin-yong JIANG1,2, Hui-ying CHEN2, Hong-ning ZHOU1, Ya-jun MA2,*()   

  1. 1 Yunnan Institute of Parasitic Diseases, Yunnan Provincial Center of Arborvirus Research, Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Yunnan Provincial Collaborative Innovation Center for Public Health and Disease Prevention and Control, Puer 665099, China
    2 Department of Tropical Infectious Disease, Second Military Medical University, Shanghai 200433, China
  • Received:2017-04-26 Online:2017-12-30 Published:2018-01-10
  • Contact: Ya-jun MA E-mail:yajun_ma@163.com
  • Supported by:
    Supported by the National Natural Science Foundation of China (No.81371848, No.30660160, No.81160357)

Abstract:

Objective To detect the knockdown resistance(kdr) gene mutations in Culex tritaeniorhynchus resistant or susceptible to DDT and deltamethrin, in order to elucidate the relationship between the resistant phenotype and kdr mutations.Methods C.tritaeniorhynchus mosquitoes were captured in Zhaoyang, Mang Shi, Jiang Cheng and Meng Lian in Yunnan Province, and exposed to DDT and deltamethrin, respectively.The resulting alive and dead ones were counted.Genomic DNA was extracted by individual mosquitoes.The kdr gene was amplified by PCR and analyzed.The frequency of kdr genotypes was estimated in resistant and susceptible samples.The relationship between kdr genotypes and resistant phenotypes was analyzed by Chi-square test.Results A total of 411 mosquitoes were genotyped for the kdr gene.Mutation was detected at codon 1014, yielding two alleles, the wild-type TTA/L and the mutant TTT/F, and three genotypes, the wild-type homozygote L/L (frequency, 96.35%; 396/411), the mutant homozygote F/F (0.73%; 3/411) and the wild/mutant heterozygous L/F (2.92%; 12/411).The frequencies of mutant genotype in DDT-resistant and -susceptible individuals were 3.42% (4/117) and 3.88% (4/103), respectively; while those in deltamethrin-resistant and -susceptible individuals were 3.96% (4/101) and 3.33% (3/90), respectively.Chi-square test revealed that there was no correlation between kdr genotype frequency and the resistance phenotypes to either DDT (χ2 = 0.034, P > 0.05) or deltamethrin (χ2 = 0.053, P > 0.05).Conclusion We found a novel L1014F mutant allele for kdr, albeit with a low frequency.There is no correlation between kdr gene mutation and the resistance phenotypes to either DDT or deltamethrin.

Key words: Culex tritaeniorhynchus, Knockdown resistance, Gene mutation

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