The role of the Aedes aegypti Epsilon glutathione transferases in conferring resistance to DDT and pyrethroid insecticides

Nongkran Lumjuan*, Shavanthi Rajatileka, Donch Changsom, Jureeporn Wicheer, Posri Leelapat, La aied Prapanthadara, Pradya Somboon, Gareth Lycett, Hilary Ranson

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

169 Citations (Scopus)

Abstract

The Epsilon glutathione transferase (GST) class in the dengue vector Aedes aegypti consists of eight sequentially arranged genes spanning 53,645 bp on super contig 1.291, which maps to chromosome 2. One Epsilon GST, GSTE2, has previously been implicated in conferring resistance to DDT. The amino acid sequence of GSTE2 in an insecticide susceptible and a DDT resistant strain differs at five residues two of which occur in the putative DDT binding site. Characterization of the respective recombinant enzymes revealed that both variants have comparable DDT dehydrochlorinase activity although the isoform from the resistant strain has higher affinity for the insecticide. GSTe2 and two additional Epsilon GST genes, GSTe5 and GSTe7, are expressed at elevated levels in the resistant population and the recombinant homodimer GSTE5-5 also exhibits low levels of DDT dehydrochlorinase activity. Partial silencing of either GSTe7 or GSTe2 by RNA interference resulted in an increased susceptibility to the pyrethroid, deltamethrin suggesting that these GST enzymes may also play a role in resistance to pyrethroid insecticides.

Original languageEnglish
Pages (from-to)203-209
Number of pages7
JournalInsect Biochemistry and Molecular Biology
Volume41
Issue number3
DOIs
Publication statusPublished - 1 Mar 2011

Keywords

  • Aedes aegypti
  • DDT dehydrochlorinase
  • Glutathione transferase
  • Insecticide resistance
  • Permethrin
  • RNA interference

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