摘要
微粒体细胞色素P450氧化酶介导的解毒代谢增强是棉铃虫Helicoverpa armigera对拟除虫菊酯类杀虫剂产生抗性的主要原因。作者前期的研究表明,CYP9A12和CYP9A14组成型过量表达与棉铃虫YGF品系对拟除虫菊酯的高水平抗性相关,CYP9A12和CYP9A14的功能表达研究结果为其参与对拟除虫菊酯抗性提供了直接证据。本研究通过对棉铃虫CYP9A17v2的克隆、mRNA表达水平和功能表达的研究,以期明确该基因是否参与棉铃虫对拟除虫菊酯的抗性。结果表明:CYP9A17v2与CYP9A12的氨基酸序列具有很高的相似性(94%)。与棉铃虫对照品系(YG)相比,CYP9A17v2在YGF抗性品系末龄幼虫脂肪体中具有10.9倍的组成型过量表达,而在中肠中未发现过量表达。用酿酒酵母Saccharomyces cerevisiae异源表达的CYP9A17v2能够代谢多种拟除虫菊酯(顺式氰戊菊酯、溴氰菊酯和氟氯氰菊酯)。据此认为CYP9A17v2组成型过量表达参与了棉铃虫对拟除虫菊酯的抗性。至此,CYP9A亚家族中已有3个P450基因(CYP9A12,CYP9A14和CYP9A17v2)被证实参与了棉铃虫对拟除虫菊酯的氧化解毒代谢。
Enhanced detoxification mediated by microsomal cytochrome P450s is a major mechanism responsible for pyrethroid resistance in Helicoverpa armigera. Our previous study showed that constitutive overexpression of CYP9A12 and CYP9A14 was associated with high levels of pyrethroid resistance in the pyrethroid-resistant YGF strain of H. armigera, and functional expression of CYP9A12 and CYPgA14 in yeast provided direct evidence on their involvement in pyrethroid resistance. In this study, molecular cloning, mRNA expression, and functional expression of cYPgA17v2 of H. armigera were investigated in order to verify possible involvement of CYP9A17v2 in pyrethroid resistance. The results showed that protein sequence of CYP9A17v2 has very high identity （94%） to that of CYP9A12. CYP9A17v2 in the fat body of the final-instar larva of the YGF strain had 10.9-fold overexpression compared with that of the control strain （YG）, but no overexpression was detected in the midgut. Functional expression in yeast （Saccharomyces cerevisiae） showed that CYP9A17v2 had the capability of metabolizing several pyrethroids （esfenvalerate,dehamethrin, and cyhalothrin）. It is so concluded that constitutive overexpression of cYPgA17v2 also contributes to pyrethroid resistance in the YGF strain of H. armigera. Together with previous findings, three P450 genes （CYP9A12, CYP9A14 and CYP9A17v2 ） from the CYP9A subfamily are confirmed to be involved in oxidative detoxification of pyrethroids in H. armigera.
出处
《昆虫学报》
CAS
CSCD
北大核心
2009年第8期852-859,共8页
Acta Entomologica Sinica
基金
国家自然科学基金项目(30471154)
