title: Expression analysis of two P450 monooxygenase genes of the tobacco cutworm moth (Spodoptera litura) at different developmental stages and in response to plant allelochemicals.
abstract: Cytochrome P450 monooxygenases (P450s) of insects are known to be involved in the metabolism or detoxification of plant allelochemicals and insecticides. Spodoptera litura (Lepidoptera, Noctuidae) is a polyphagous moth responsible for severe yield losses in many crops. In this study, two full-length P450 genes, CYP6B48 and CYP6B58, were cloned from S. litura. The cDNA sequences encode proteins with 503 and 504 amino acids, respectively. Phylogenetic analysis revealed that CYP6B48 and CYP6B58 belong to the CYP6B subfamily of P450s. Quantitative real-time PCR analyses showed that CYP6B48 and CYP6B58 were expressed only at larval stage, but not at pupal and adult stages. The highest levels of transcripts were found in the midguts and fat bodies of the larvae. No expression was detected in the ovary or hemolymph. Feeding with diets containing cinnamic acid, quercetin, or coumarin did not affect expression of CYP6B48. In contrast, diet supplemented with xanthotoxin dramatically increased the levels of CYP6B48 transcript in the midgut and fat bodies. Larvae fed with flavone had high levels of transcript of CYP6B48 in the midgut, whereas only slightly elevated levels were found in the fat bodies. Effects of the tested allelochemicals on CYP6B58 expression were minor. Hence, our findings show that S. litura responds to specific allelochemicals such as xanthotoxin with the accumulation of CYP6B48 transcripts, suggesting that specific signals in the food control the insect's ability to convert toxic allelochemicals to less harmful forms at the transcriptional level.
authors.affiliation: Key Laboratory of Tropical Agro-environment, Ministry of Agriculture, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Rui-Long
authors.initials: RL
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Christian
authors.initials: C
authors.lastname: Staehelin
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Xin
authors.forename: Yi-Juan
authors.initials: YJ
authors.lastname: Su
authors.forename: Ren-Sen
authors.initials: RS
authors.lastname: Zeng
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006458:Hemolymph / Q000502:physiology; D019476:Insect Proteins / Q000235:genetics; D007814:Larva / Q000502:physiology; D008730:Methoxsalen / Q000494:pharmacology; D008969:Molecular Sequence Data; D010053:Ovary / Q000502:physiology; D010675:Pheromones / Q000494:pharmacology / Q000502:physiology*; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D018411:Spodoptera / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development*; D014026:Nicotiana / Q000378:metabolism
chemical_list: D019476:Insect Proteins; D010675:Pheromones; D003577:Cytochrome P-450 Enzyme System; D008730:Methoxsalen