Molecular Studies On The Acetylcholinesterases In Two Wheat Aphids, Rhopalosiphum Padi (Linnaeus) And Sitobion Avenae(Fabricius)

Acetylcholinesterase (AChE, EC3.1.1.7) is vital for neuro-function of animals and also one of the most efficient targets for organophosphate and carbamate insecticides. So, it has been extensively studied and its alternation in sensitivity has been proved as an important mechanism for insecticide resistance. Some mutations of AChE genes associated with insecticides resistance have also been reported in many insects or spiders, including Drosophila melanogaster, Leptinotarsa decemlineata, Musca domestic, Helicoverpa armigera, Bactrocera oleae, Tetranychus urtica, Culex pipiens, Culex quinquefasciatus, Anopheles gambiae, Myzus persicae, Culex tritaeniorhynchus, and Aphis gossipii. However, in some other insects, such as Nephotettix cincticep, Bemisia Trialeurodes and Trialeurodes vaporariorum, even the insensitive AChE was confirmed with biochemistry methods, no related mutations in the cloned AChE genes were found. So, it was deduced that there might be some other AChE genes in these insects, which produce the insensitive AChE and result in insecticide resistance.Since Li and Han first cloned two different AChE genes from A. gossypii in 2002, entomologists have paid great attention on the existing and function of the two AChE genes in various insects. Seven insects belong to 4 order have been confirmed to have different AChE genes. But, D. melanogaster was found to have only one, even its whole genome was searched through. So, questions arose as what insects have two AChE genes, if two AChE gene are both necessary for these insects, if the two AChE have different function and how they arise in evolution.To concentrated on these questions, our work were performed with the financial aids by the National Natural Science Foundation of China (NSFC, Grant No. 30370943), and with the very important agriculture insects, Rhopalosiphum padi and Sitobion avenae, as test animals. The results were summarized as fellows:1. Two different AChE genes existing in both R. padi and S. avenaeUsing degenerate primers and RT-PCR technique, Two different cDNA fragments of AChE genes were cloned from both Rhopalosiphum padi (Linnaeus) and Sitobion avenae (fabricius) and were named as Rp.ace1, Rp.ace2,Ma.ace1 and Ma.ace2, respectively. They were 282, 282, 264 and 572 bp in length, and encodes 94, 94, 88 and 190 amino acids,...