The Biochemical Response Mechanism Of Plutella Xylostella Populations In The Field Of Diamide Insecticides Stress

To elucidate the relationship between the metabolism of chlorantraniliprole and ABC transporter(ATP-binding cassette transporter) in diamondback moth, Plutella xylostella. The ABCC1-ABCC5 mRNA expression in different strains of the diamondback moth and LC50 of chlorantraniliprole treated susceptible strain were determined by using real-time quantitative RT-PCR. Then the expression of ABCC3,ABCC4 and ABCC5 in the different development stages and different tissues of 4instar larvae were detected. All 5 genes were up-regulated in the resistant strain(CHR)and significantly higher than those in the susceptible one(CHS). In the susceptible strain treated with LC50 of chlorantraniliprole, the expression of ABCC3, ABCC4 and ABCC5 were 2.16, 2.81 and 1.85 times higher than the untreated control, respectively.While ABCC1 and ABCC2 were down-regulated and were only 65.8% and 37.2% of the control, respectively. The expression of ABCC3 mRNA in the larval stage and the male adult were significantly higher than those in other developmental stages. The expression of ABCC4 m RNA had no obvious difference among all stages. The expression of ABCC5 m RNA in the third instar larvae was significantly higher than that in other developmental stages. In the 4 instar larvae, the expression of ABCC3,ABCC4 and ABCC5 mRNA in the midgut were significantly higher than that in other tissues. The expression of ABCC4 m RNA was significantly higher than that of ABCC3 and ABCC5 in the same tissue. The results indicated that ABCC3, ABCC4 and ABCC5 may play a detoxification role in the chlorantraniliprole metabolism in diamondback moth and ABCC4 gene may play a greater role, which provided the base for further study on the relationship between ABCC1-ABCC5 and the metabolism ofchlorantraniliprole.The toxicity of eight kinds of ecdysone derived from methoxyfenozide mighit be related to thier specific structure. The best effect was obtained besting the treatments with compound ?-8, one of compound ? series. The mortality rate of the moth treated with 100 ppm of ?-8 was 75.70%, which was significantly higher than that of other compounds including Methoxyfenozide. This may be due to a special group with high insecticidal activity in ?-8. The compounds of the ? series were generally superior to the ? series, which indicated that the common compound groups had better effects than the ? series. The mortality of the moth larva treated with ? series compounds at the 100 ppm concentration was more than 10%, of which the lowest mortality was 17.23% resulted by ?-. The moth mortality by ?series of compounds at the concentration 100 ppm was less than10%, of which the best was IV-7 resulting the moth mortality 8.39%, and the worst was ?-8, the mot mortality rate was 2.89% only. The control, methoxyfenozide at the concentration of100 ppm, the moth mortality was 67.95%.The purpose of this study is to provide theoretical basis for the development of new insecticide. The toxicity of ?-8 compound to the moth is higher than that of methoxyfenozide. This would be valuable for the development of new insecticide,which might play an important role in delaying resistance of diamondback moth,Plutella xylostella, to the common insecticides.