Acetylcholinesterase (AChE) is the target of organophosphate and carbamate pesticides. Organophosphate resistance is worldspread in the cotton bollworm[Helicoverpa armigera (Hübner)]. With the degenerate primers we amplified a 281 bp cDNA fragment of acetylcholinesterase (AChE) gene in H. armigera by reverse transcription-polymerase chain reaction (RT-PCR) method using total RNA extracted from 4th larva as the template. The cDNA fragment was inserted into pGEMT vector and then cloned. The deduced amino acid sequence of AChE consisted of 94 residues. The sequence analysis indicated that the deduced amino acid sequence of the cDNA fragment shares high identity with AChE gene from other published insects and animals. The acquired sequence had 84%,79%,74%,70%,70%,72%,68%,61%,55% and 57% of amino acid residues identical to those of Leptinotarsa decemlineata(L.d.), Nephotettix cincticeps(N.c.),Anopheles stephensi(A.s.), Aedes aegypti(A.a.), Lucilia cuprina(L.c.), Drosophila melanogaster(D.m.), Musca domestica(M.d.), Meloidogyne incognita(M.i.), Torpedo californica(T.c.) and Gallus gallus(G.g.), respectively. All these results firmly established that the amplified cDNA fragment was the partial sequence of AChE gene in H. armigera. This is the first report of partial cDNA sequence of AChE in H. armigera.
