Department of Entomology, China Agricultural University, Beijing, China.
Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, UK.
J Econ Entomol. 2019 May 22;112(3):1365-1371. doi: 10.1093/jee/toz021.
Insect cytochrome P450 monooxygenases play an important role in plant allelochemical detoxification. In this study, a full-length gene CYP305A1 of the P450 Clan 2 family was cloned from Aphis gossypii Glover, and its promoter was identified and characterized. The transcript level of CYP305A1 and its promoter activity were significantly induced by two plant allelochemicals, gossypol and 2-tridecanone. Furthermore, the 5'-end promoter region from -810 to +62 bp was demonstrated to be essential for basal transcriptional activity of CYP305A1, and the promoter region from -810 to -581 bp was shown as an essential plant allelochemical responsive element and had a cis-element 5'-CACACTA-3' as the binding site of aryl hydrocarbon receptor. Interestingly, there was an identical overlapping region of 1,094 bp between CYP305A1 promoter and the venom protease gene. When the expression of CYP305A1 gene was knocked down by RNA interference with CYP305A1 dsRNA, the expression of the venom protease gene was decreased. However, the knockdown of the expression of the venom protease gene did not affect the CYP305A1 expression. These results provide important insights for understanding the functions of P450 genes and the regulatory mechanism of P450 gene expressions in the resistance of Aphis gossypii Glover to plant allelochemicals.
昆虫细胞色素 P450 单加氧酶在植物化感物质解毒中发挥着重要作用。本研究从棉蚜中克隆得到 P450 家族 2 簇全长基因 CYP305A1，并对其启动子进行了鉴定和特征分析。CYP305A1 及其启动子的转录水平均被两种植物化感物质——棉酚和 2-十三酮显著诱导。此外，-810 至+62bp 的 5'-端启动子区域对于 CYP305A1 的基础转录活性是必需的，而-810 至-581bp 的启动子区域则作为一个必需的植物化感物质响应元件，具有一个顺式作用元件 5'-CACACTA-3'，作为芳香烃受体的结合位点。有趣的是，CYP305A1 启动子和毒液蛋白酶基因之间存在一个 1094bp 的重叠区域。当用 CYP305A1 dsRNA 进行 RNA 干扰使其表达量降低时，毒液蛋白酶基因的表达也随之降低。然而，毒液蛋白酶基因表达的敲低并不影响 CYP305A1 的表达。这些结果为理解 P450 基因的功能以及棉蚜对植物化感物质抗性中 P450 基因表达的调控机制提供了重要的见解。
