摘要
The cytochrome P450 monooxygenase （cytochrome P450） gene superfamily comprises many genes that may be involved in the biotransformations of pesticides and other xenobiotics. To date, very little is known about cytochrome P450 genes in the oriental migratory locust, Locusta migratoria manilensis. In this study, we carried out a genomewide analysis ofcytochrome P450 genes of the locust to identify putative cytochrome P450 genes and characterize their expression responses to insecticide exposures. We identified 15 cytochrome P450-1ike genes from a locust expressed sequence tag database （LocustDB）. Reverse transcription polymerase chain reaction （RT-PCR） analysis showed that most cytochrome P450-1ike genes displayed different tissue and developmental stage expression patterns. However, most of them were predominantly expressed in the midgnt, gastric caeca, fatbodies, and/or hindgut. Biochemical analysis showed that cytochrome P450 was differentially affected by three different insecticides. Deltamethrin caused significant inductions in 12 h at LD30 （dose to kill 30% of the tested individuals） in the nymphs, whereas malathion and carbaryl did not have significant effect on cytochrome P450 enzyme activity. Further RT-PCR analysis Showed significant increases of transcriptions of several cytochrome P450 genes in deltamethrin-treated locusts. Thus, the increased cytochrome P450 enzyme activity is likely due to increased transcriptions of multiple cytochrome P450 genes in response to deltamethrin exposure. These results are expected to help us better understand the interactions between insecticides and major detoxification enzymes, and possible changes of the susceptibility to other insecticides in deltamethrin-treated insects at various molecular levels.
The cytochrome P450 monooxygenase （cytochrome P450） gene superfamily comprises many genes that may be involved in the biotransformations of pesticides and other xenobiotics. To date, very little is known about cytochrome P450 genes in the oriental migratory locust, Locusta migratoria manilensis. In this study, we carried out a genomewide analysis ofcytochrome P450 genes of the locust to identify putative cytochrome P450 genes and characterize their expression responses to insecticide exposures. We identified 15 cytochrome P450-1ike genes from a locust expressed sequence tag database （LocustDB）. Reverse transcription polymerase chain reaction （RT-PCR） analysis showed that most cytochrome P450-1ike genes displayed different tissue and developmental stage expression patterns. However, most of them were predominantly expressed in the midgnt, gastric caeca, fatbodies, and/or hindgut. Biochemical analysis showed that cytochrome P450 was differentially affected by three different insecticides. Deltamethrin caused significant inductions in 12 h at LD30 （dose to kill 30% of the tested individuals） in the nymphs, whereas malathion and carbaryl did not have significant effect on cytochrome P450 enzyme activity. Further RT-PCR analysis Showed significant increases of transcriptions of several cytochrome P450 genes in deltamethrin-treated locusts. Thus, the increased cytochrome P450 enzyme activity is likely due to increased transcriptions of multiple cytochrome P450 genes in response to deltamethrin exposure. These results are expected to help us better understand the interactions between insecticides and major detoxification enzymes, and possible changes of the susceptibility to other insecticides in deltamethrin-treated insects at various molecular levels.
