Transcription profiling of eight cytochrome P450s potentially involved in xenobiotic metabolism in the silkworm, Bombyx mori

Cytochrome P450 (CYP) is a multifunctional super gene family, some of which play an important role in pesticide resistance. In this research, we used a real-time quantitative RT-PCR method, and a novel strategy, to measure the transcriptional level per gene copy using an exogenous RNA reference and DNA reference. The transcription levels of eight P450 genes in different tissues of fifth instar Bombyx mori larvae and their responses to pesticides (dichlorvos and deltamethrin) and sodium fluoride (NaF) were investigated. The results show different levels and patterns of expression of the different P450s in the various tissues observed. The P450s can be induced by pesticide and fluoride, but their responses to each are different. The results of this research are helpful in studying the tissue-specific expression of P450s in B. mori, and in developing new pesticide resistant silkworm varieties.