Mutations in acetylcholineaterase[실제는 acetylcholinesterase] and sodium channel associated with insecticide resistance in Anopheles sinensis wiedemann (Diptera: Culicidae) and resistance detection by PASA-based genotyping methods

Abstract

Anopheles sinensis is a major vector mosquito of malaria, which is the most important vector-borne disease in Korea. Intensive use of chemical agents including pyrethroids and organophosphates (OPs) for the control of agricultural and medical arthropod pests was quickly followed by development of resistance in a variety of arthropod species including An. sinensis. Target site insensitivity is one of the major mechanisms of insect resistance against OPs and pyrethroids. The Leu1014Phe mutation in voltage-sensitive sodium channel gene conferring knockdown resistance (kdr) against pyrethroids and the Gly119Ser mutation in acetylcholinesterase-1 gene (ace-1) conferring OP resistance are highly conserved. To determine the presence or absence of these mutations, we PCR-amplified and sequenced both the IIS5-6 fragment of the sodium channel gene and the exon 3 of the ace1 gene from an insecticide-resistant field population or An. sinensis. Sequencing results revealed that the acetylcholinesterase-1 Gly119Ser mutation is present as in other OP-resistant mosquito species and the well-known Leu1014Phe sodium channel mutation is found along with a novel Leu1014Cys mutation. To determine the correlation between resistance phenotype and the three sodium channel genotypes, permethrin resistance level of four regional populations of An. sinensis were assessed by immersion method and compared with each population¡¯s sodium channel sequence. The relatively susceptible Ansan (LC50 = 0.12) and Paju (LC50 = 1.3) populations exhibited high frequency of TTG (Leu) genotype as expected. In contrast, moderately (Jeonju, LC50 = 14.9) and highly (Gurye, LC50 = 51.3) resistant populations showed high frequencies of TTT (Phe), implying that TTT genotype is likely associated with pyrethroid resistance in An. sinensis.