CYP6B2 Expression in Insecticide-Resistant and -Suspcitible Strains
of Helicoverpa armigera

WU Jun, ZHUANG Pei-Jun and TANG Zheng-Hua^*
( Shanghai Institute of Entomology, the Chinese Academy of Sciences, Shanghai 200025, China )
PAN Hua and WU Xiang-Fu
( Shanghai Institute of Biochemistry, the Chinese Academy of Sciences, Shanghai 200031, China )

Abstract　　A fragment of CYP6B2 gene was obtained from the midgut cDNA library of the fifth instar larvae of the ballworm (Helicoverpa armigera) with RT-PCR. The product of 627 bp was cloned and sequenced. The results of dot blotting analysis of mRNA proved that CYP6B2 is expressed at higher level (mRNA) in an insecticide-resistant strain than in a susceptible strain, showing that the regulation was at transcription level. The mRNA is induced by pyrethroid in susceptible, but not in the insecticide-resistant strains. We guess that mutation in the 5′ upstream regulator of the insecticide-resistant strain may lead to the difference in the expression level between resistant and susceptible strains.
Key Words　　Helicoverpa armigera; insecticide-resistance; cytochrome P450; RT-PCR; total RNA dot blotting

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