Expression of CYP4G19 and pyrethroid-resistance of Blattella germanica.

Objective To investigate the correlation between pesticide resistance and the expression of CYP4G19 in German cockroaches.Methods German cockroaches collected in Shenzhen area were used in this study.Resistant index of the wild type German cockroaches to pyrethroid "Jia Chong Qing" was determined using the Film Contact Method.RT-PCR was used to analyze the expression level of CYP4G19 gene.siRNA was used to knockdown the expression of CYP4G19.Protein expression of CYP4G19 was evaluated using immunohistochemical method.Results Resistant index(3.88) of wild type German cockroaches was significantly higher than the sensitive strains.The expression levels of CYP4G19 mRNA in the wild types are higher than the sensitive strains.After silencing of CYP4G19 expression,CYP4G19 protein expression level was obviously decreased,and the resistant index was reduced in a time dependent manner.Conclusion Results from this study indicated that the transcription and translation of CYP4G19 gene are up-regulated in pyrethroid resistant strains.The level of pesticide resistance in the wild strains was slightly decreased after silencing of CYP4G19 expression,indicating that the expression of CYP4G19 is correlated with the pesticide resistance in German cockroaches.