Resistance-associated point mutations of organophosphate insensitive acetylcholinesterase, in the olive fruit fly Bactrocera oleae
Article first published online: 25 JUL 2002
Insect Molecular Biology
Volume 11, Issue 4, pages 329–336, August 2002
How to Cite
Vontas, J. G., Hejazi, M. J., Hawkes, N. J., Cosmidis, N., Loukas, M. and Hemingway, J. (2002), Resistance-associated point mutations of organophosphate insensitive acetylcholinesterase, in the olive fruit fly Bactrocera oleae. Insect Molecular Biology, 11: 329–336. doi: 10.1046/j.1365-2583.2002.00343.x
- Issue published online: 25 JUL 2002
- Article first published online: 25 JUL 2002
- Received 19 November 2001; accepted after revision 19 April 2002.
- Bactrocera oleae;
- AChE cDNA;
- insecticide resistance
A 2.2-kb full length cDNA containing an ORF encoding a putative acetylcholinesterase (AChE) precursor of 673 amino acid residues was obtained by a combined degenerate PCR and RACE strategy from an organophosphate-susceptible Bactrocera oleae strain. A comparison of cDNA sequences of individual insects from susceptible and resistant strains, coupled with an enzyme inhibition assay with omethoate, indicated a novel glycine-serine substitution (G488S), at an amino acid residue which is highly conserved across species (G396 of Torpedocalifornica AChE), as a likely cause of AChE insensitivity. This mutation was also associated with a 35–40% reduction in AChE catalytic efficiency. The I199V substitution, which confers low levels of resistance in Drosophila, was also present in B. oleae (I214V) and in combination with G488S produced up to a 16-fold decrease in insecticide sensitivity. This is the first agricultural pest where resistance has been associated with an alteration in AChE, which arises from point mutations located within the active site gorge of the enzyme.