谷胱甘肽S-转移酶(GSTs)是多功能酶,昆虫GSTs在杀虫剂的代谢中起着关键作用。Grapholitamolesta是一种世界性害虫,对水果行业造成巨大的经济损失。然而,目前还不清楚吡虫啉是如何,果园中常用的杀虫剂,被G.molesta代谢。在本研究中,增效剂马来酸二乙酯(DEM),抑制GST活性,对吡虫啉表现出22倍的协同作用。两个新的GST基因,GmGSTD2(OR096251)和GmGSTD3(OR096252),被鉴定并成功克隆,在Malpighian管中显示最高的表达。通过RNA干扰敲除GmGSTD2和GmGSTD3,吡虫啉治疗后,将G.molesta的死亡率从28%增加到47%。重组GmGSTD2和GmGSTD3蛋白均表现出1-氯-2,4-二硝基苯(CDNB)活性,并且可以在体外被吡虫啉抑制。GmGSTD2最大抑制为60%,GmGSTD3最大抑制为80%。这些结果表明,GSTs参与了吡虫啉的代谢,GmGSTD2和GmGSTD3在该过程中起关键作用。
Glutathione S-transferases (GSTs) are multifunctional enzymes, and insect GSTs play a pivotal role in the metabolism of insecticides. Grapholita molesta is a worldwide pest that causes substantial economic losses to the fruit industry. However, it remains unclear how
imidacloprid, a commonly used insecticide in orchards, is metabolized by G. molesta. In the present study, the synergist diethyl maleate (DEM), which inhibits the GST activity, exhibited a 22-fold synergistic ratio against
imidacloprid. Two new GST genes, GmGSTD2 (OR096251) and GmGSTD3 (OR096252), were identified and successfully cloned, showing the highest expression in the Malpighian tubes. Knockdown of GmGSTD2 and GmGSTD3 by RNA interference, increased the mortality of G. molesta from 28% to 47% following
imidacloprid treatment. Both recombinant GmGSTD2 and GmGSTD3 proteins exhibited 1-chloro-2,4-dinitrobenzene (CDNB) activity and could be inhibited by
imidacloprid in vitro, with maximum inhibition was 60% for GmGSTD2 and 80% for GmGSTD3. These results suggested that GSTs participate in the metabolism of
imidacloprid with GmGSTD2 and GmGSTD3 playing key roles in this process.