棉铃虫P450基因CYP6AE12和CYP9A18的克隆与mRNA表达水平

采用RT-PCR和RACE技术克隆到2个新的棉铃虫细胞色素P450基因：CYP6AE12和CYP9A18。CYP6AE12的cDNA编码区长1 569 bp，编码523个氨基酸；CYP9A18的cDNA编码区长1 590 bp，编码530个氨基酸。用实时定量PCR技术分析了这2个基因在棉铃虫YS敏感品系和YS-FP抗性品系(由氰戊菊酯加辛硫磷混剂筛选YS品系而得) 6龄幼虫脂肪体和中肠中mRNA的表达水平。结果表明：CYP6AE12和CYP9A18的mRNA表达具有组织特异性，CYP6AE12在脂肪体中表达量较高，而CYP9A18在中肠中的表达量较高。与相对敏感品系YS相比，CYP6AE12在YS-FP抗性品系中肠和脂肪体中的mRNA表达量分别为YS品系的3.6倍和1.3倍；CYP9A18在YS-FP品系中肠和脂肪体的mRNA表达量分别为YS品系的0.3倍和1.0倍。CYP6AE12的过量表达与YS-FP品系棉铃虫的抗药性可能有一定关系。

Cloning and mRNA expression levels of cytochrome P450 genes CYP6AE12 and CYP9A18 in the cotton bollworm,Helicoverpa armigera (Hübner)

Two novel P450 genes (CYP9A18 and CYP6AE12) from the insecticide-resistant strain (YS-FP) of Helicoverpa armigera (Hübner) were cloned with RT-PCR and RACE. The coding region of CYP6AE12 cDNA is 1 569 bp, encoding a protein of 523 amino acids, while that of CYP9A18 cDNA is 1 590 bp, encoding a protein of 530 amino acids. Using real-time quantitative PCR, mRNA expression levels of CYP6AE12 and CYP9A18 were compared between the resistant strain YS-FP (derived from a susceptible strain YS through laboratory selection) and the YS strain respectively. The results showed that the expression of CYP6AE12 was higher in fat body than in midgut in the 6th instar larvae of both strains, whereas the expression of CYP9A18 was higher in midgut than in fat body. Compared with the YS strain, CYP6AE12 in fat body and midgut of the YS-FP strain was 1.3- and 3.6 fold over-expressed respectively, while CYP9A18 was not over-expressed in both midgut and fat body of the YS-FP strain. The results suggested that CYP6AE12 was probably involved in pyrethroid resistance in the resistant YS-FP strain of H. armigera.