Characterization of novel esterases in insecticide-resistant mosquitoes.
In the mosquito Culex pipiens complex (Diptera: Culicidae), the amplification of carboxylesterase genes is an important mechanism providing resistance to organophosphate insecticides. Various amplified alleles at the Ester locus have been identified over the world. In this study, two newly detected Ester alleles, Ester(B10) and Ester(11) (including associated Ester(A11) and Ester(B11)), coding for esterases B10 and A11-B11, respectively, are characterized qualitatively and quantitatively. A high molecular identity is observed both at the nucleotide level and at the deduced amino acid level among the known Ester alleles. Real-time quantitative PCR results suggest 2.5-fold amplification of the Ester(B10) allele, 36.5-fold amplification of the Ester(A11) allele, and 19.1-fold amplification of the Ester(B11) allele. The ca. 2-fold difference in amplification level between Ester(A11) and Ester(B11) may indicate a new model for the esterase amplification. Bioassays show that these two resistant Ester alleles only can confer moderate or low resistance to the tested organophosphate insecticides.
Cui
Feng
F
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China.
Weill
Mylene
M
Berthomieu
Arnaud
A
Raymond
Michel
M
Qiao
Chuan-Ling
CL
D000483:Alleles; D000818:Animals; D003001:Cloning, Molecular; D003465:Culex / Q000201:enzymology* / Q000235:genetics; D004586:Electrophoresis; D004950:Esterases / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D007305:Insecticide Resistance / Q000235:genetics; D007306:Insecticides; D010755:Organophosphates; D017422:Sequence Analysis, DNA
D019476:Insect Proteins; D007306:Insecticides; D010755:Organophosphates; D004950:Esterases