Molecular Cloning And Relative Expression Analysis Of NADPH-Cytochrome P450Reductase And NADH-cytochrome B5Reductase Gene In Whitefly (Bemisia Tabaci)

The whitefly Bemisia tabaci (Gennadius)(Hemiptera:Aleyrodidae) is a pest of many agricultural systems。Since the1980s, a large number of pesticides were used to control whitefly. Frequent and irrational use of pesticides resulted in resistance to many insecticides. Enhanced detoxification enzymes and target insensitivity (target insensitivity).are the main mechanism of pest resistance. Cytochrome P450System plays an important role on insecticide resistance in the whitefly.NADPH-cytochrome P450reductase (EC1.6.2.4, NADPH-cytochrome P450reduetase, CPR) and NADH-cytochrome b5reductase (EC.1.6.6.2, NADH-cytochrome b5reduetase, CBR) are important part of cytochrome P450oxidoreductase, which play important role in cytochrome P450-mediated oxidation-reduction reaction. In this paper, full-length of CPR and CBR were obtained by reverse transcription stragety and Race strategies. The expression lecels of CPR and CBR genes of B. tabaci in different organs, different stages and different strains were investigated. Those research will provided a deep view in the role role of cytochrome P450system in the formation of whitefly resistance and the process of whitefly development.1、Full length cloning and sequences analysis of Whitefly CPR and CBR genesThe whitefly full-length CPR and CBR cDNA were cloned by RT-PCR and Race strategies.The CDS of CPR gene was2037bp, which encoding678amino acids residues and containing typical CPR protein domains. There are two forms CBR-A and CBR-B in the5’term of CBR gene. The length of CBR-A cDNA is1871bp which encoding336amino acids and containing75bp in5’UTL and785bp in3’UTL. The length of CBR-B cDNA is1913bp which encoding313amino acids and containing186bp in5’UTL and785bp in3’ UTL.2、Differences in the expression of genes whitefly CPR and CBR different developmental stages and in different tissuesThe assay of whitefly CPR and CBR expreson levels in different stages showed both genes expressed through the whole process of development; the expression levels were significantly lower in the egg stage than others;there is no significantly difference between female and male in both genes expression.The assay of whitefly CPR and CBR expreson levels in different origon indicated both genes expression in the abdomen is significantly higher than the expression in other origons.3、The expression levels of CPR and CBR genes both resistance and sensitive strain of whiteflyThe expression levels of CPR genes in resistance strain show no signficant difference compared with sensitive strans. Those indicatesd CPR genes could not involve in resistance mechanism. However, the expression levels of CBR gene was signficantly different between sensitive strain and bifenthrin-resistance strain, while the changement of expression level of CBR genes were not reach the signficant levels. The different expression levels of CBR genes in differnt strans showed the function of CBR genes contributed to the ability of anti-bifenthrin.