棉铃虫P450基因CYP9A12酵母表达产物对拟除虫菊酯的代谢作用

Metabolism of pyrethroids by Helicoverpa armigera cytochrome P450 gene CYP9A12 heterologously expressed in Saccharomyces cerevisiae

细胞色素P450氧化酶解毒代谢作用增强是棉铃虫Helicoverpa armigera对拟除虫菊酯类杀虫剂产生抗性的主要原因,棉铃虫细胞色素P450氧化酶基因CYP9A12的组成型过量表达与拟除虫菊酯抗性相关。为了进一步明确棉铃虫细胞色素P450氧化酶基因CYP9A12与拟除虫菊酯类杀虫剂抗性的关系,采用酿酒酵母Saccharomyces cerevisiae表达系统异源表达了CYP9A12基因,检测了该基因的酵母表达产物对溴氰菊酯、氟氯氰菊酯、甲氰菊酯和联苯菊酯4种药剂的离体代谢作用。结果表明:含有CYP9A12外源基因的重组酵母细胞裂解液对溴氰菊酯、氟氯氰菊酯和联苯菊酯的代谢率分别为8.58,5.85和3.94pmol/min·mg protein,而没有检测到对甲氰菊酯的代谢。本研究表明了CYP9A12具有代谢多种拟除虫菊酯的能力,也为CYP9A12参与拟除虫菊酯的解毒代谢提供了直接证据。

Enhancement in cytochrome P450-catalyzed oxidative metabolism is a major factor responsible for pyrethroid resistance in cotton bollworm Helicoverpa armigera, and constitutive overexpression of CYP9A12 was associated with pyrethroid resistance. To examine the involvement of cytochrome P450 gene CYP9A12 in pyrethroid metabolism, we measured the metabolism of dehamethrin, cyhalothrin, fenpropathrin and bifenthrin by CYP9A12 expressed in Saccharomyces cerevisiae. The metabolism rates of heterologously expressed CYP9A12 against dehamethrin, cyhalothrin and fenpropathrin were 8.58, 5.85 and 3.94 pmol/min· mg protein, respectively. No fenpropathrin metabolism was detected in CYP9A12-containing yeast cell lysates. This study showed that CYP9A12 has the capacity to metabolize several pyrethroids, providing direct evidence for the involvement of CYP9A12 in pyrethroid resistance in H. armigera.