Construction Of A Drosophila Melanogaster Near-Isogenic Line From Alcohol Dehydrogenase Mutant ADHN1 And Canton-S And Their Toxicity Responses To Three Insecticides

Insects are major biotic factors that cause losses in agricultural production.The control of the insect pestshas mainly relied on insecticides. The knowledges on the mode of actions not only improve the efficiencies of insecticides, but also effectively manage insecticide resistances. In the present paper, a Drosophila melanogaster near-isogenic line from alcohol dehydrogenase mutant adhnl and Canton-S was constructed. The toxicity responses of the two strains to three representative insecticide endosulphan, butene-fipronil and imidacloprid were determined. The influence of the three insecticides on the expression levels of eleven genes involved in insulin-like, ecdysone and juvenile hormone signaling pathways was evaluated, and the possible toxicity mechanisms of the three insecticides to reproduction was discussed. These results may provide helps for insecticide application.A Construction of a Drosophila melanogaster near-isogenic lineFlypub full of 70% ethanol was found to sedate the alcohol dehydrogenase mutant adhnl more quickly than Canton-S. Moreover, a Bi-PASA was developed to check the mutation of adhnl. We then backcrossed alcohol dehydrogenase mutant adhnl and Canton-S and identified the F2 generations with Flypuband Bi-PASA to obtain adhnl/adhnl offsprings. We repeated the backcross for 10 times and finally constructed an adhnl near-isogenic line.B Toxicity responses to the three insecticidesThe negative effects of endosulphan, butane-fipronil and imidacloprid on oviposition and larval performance in Canton-S and the adhnlnear-isogenic line were determined. (1). Females from Canton-S and the adhnl near-isogenic line preferred to lay their eggs on diets containing endosulphan or butene-fipronil, but rejected to oviposite on imidacloprid-contained diet. (2). The fecundity of CS females was significantly higher than that of the females in adhn1 near-isogenic line. Butene-fipronil stimulated oviposition by CS females, whereas endosulphan and imidacloprid enhanced oviposition by the females in adhnl near-isogenic line.(3). The hatchabilities of the eggs from both CS and the adhnl near-isogenic line were more than 95%. Moreover, the hatchabilities were not affected by the three insecticides. (4). The sexual ratio in either CS or the adhnl near-isogenic line was approximately 1.0. Ingestion of imidacloprid but not endosulphan and butene-fipronil significantly reduced the sexual ratio in CS strain, whereas increased the sexual ratio inthe adhnl near-isogenic line. (5). Ingestion each of the three insecticides delayed the larval development in CS strain but not in the adhnl near-isogenic line.C The three insecticides affected gene transcriptionThe affects of endosulphan, butene-fipronil and imidacloprid on the expression levels of genes involved in insulin-like (ILP2, ILP3, ILP5, ILP7and InR), ecdysone (CYP307A1, EcR and Broad) and juvenile hormone(JHAMT, Met and Kr-hl) signaling pathways were evaluated in the females by q-PCR. Ingestion of endosulphan in CS strain upregulated ILP2, ILP5, ILP7, CYP307A1 and JHAMT. Ingestion ofbutene-fipronil in CS strain enhanced the expression of ILP2 and ILP5. Moreover, ingestion of imidacloprid by the adhnl near-isogenic line increased the expression of Kr-hl and Met. It was suggested that the regulation mechanisms to oviposition wer differentamong endosulphan, butene-fipronil and imidacloprid.