Identification of Two Cytochrome Monooxygenase P450 Genes, CYP321A7 and CYP321A9, from the Tobacco Cutworm Moth (Spodoptera Litura) and Their Expression in Response to Plant Allelochemicals.

Larvae of the polyphagous tobacco cutworm moth, () encounter potentially toxic allelochemicals in food. It is therefore important for to produce detoxification enzymes such as cytochrome P450 monooxygenases (P450s). In this study, we have identified two novel cytochrome P450 genes of , named and Phylogenetic analysis indicated that they belong to the subfamily. Expression levels of these genes at different development stages were determined by real-time quantitative polymerase chain reaction (PCR). The highest expression was found in the midgut and the fat body. Larvae fed with a diet supplemented with xanthotoxin or coumarin showed a strongly increased expression of and in the midgut and fat body as compared to larvae that consumed a control diet. In contrast, larvae consuming a diet containing aflatoxin B1 or quercetin did not induce the expression of these genes. and showed different expression profiles with respect to certain allelochemicals. For example, a diet containing cinnamic acid stimulated the expression of , whereas no changes were observed for . We suggest that the fine tuning of P450 gene expression is an important adaptation mechanism that allows polyphagous larvae to survive in a changing chemical environment.