Abstract：
The brown planthopper (BPH), Nilaparvata lugens is a devastating agricultural pest of rice, and they have developed resistance to many pesticides. In this study, we assessed the response of BPH nymphs to nitenpyram, imidacloprid, and etofenprox using contact and dietary bioassays, and investigated the underlying functional diversities of BPH glutathione-S-transferase (GST), carboxylesterase (CarE) and cytochrome P450 monooxygenase (P450) against these insecticides. Both contact and ingestion toxicity of nitenpyram to BPH were significantly higher than either imidacloprid or etofenprox. Under the LC50 concentration of each insecticide, they triggered a distinct response for GST, CarE, and P450 activities, and each insecticide induced at least one detoxification enzyme activity. These insecticides almost inhibited the expression of all tested GST, CarE, and P450 genes in contact bioassays but induced the transcriptional levels of these genes in dietary bioassays. Silencing of NlGSTD2 expression had the greatest effect on BPH sensitivity to nitenpyram in contact test and imidacloprid in dietary test. The sensitivities of BPH to insecticide increased the most in the contact test was etofenprox after silencing of NlCE, while the dietary test was nitenpyram. Knockdown of NlCYP408A1 resulted in BPH sensitivities to insecticide increasing the most in the contact test was nitenpyram, while the dietary test was imidacloprid. Taken together, these findings reveal that NlGSTD2, NlCE, and NlCYP408A1 play an indispensable role in the detoxification of the contact and ingestion toxicities of different types of insecticides to BPH, which is of great significance for the development of new strategies for the sucking pest control.
摘要：
褐飞虱（BPH），Nilaparvatalugens是水稻的一种毁灭性农业害虫，他们已经对许多杀虫剂产生了抗药性。在这项研究中,我们评估了BPH若虫对Nitenpyra的反应，吡虫啉,和etofenprox使用接触和饮食生物测定法，并研究了BPH谷胱甘肽-S-转移酶（GST）的潜在功能多样性，羧酸酯酶（CarE）和细胞色素P450单加氧酶（P450）对这些杀虫剂。硝基吡喃对BPH的接触和摄入毒性均显着高于吡虫啉或依托芬普司。在每种杀虫剂的LC50浓度下，他们引发了对商品及服务税的不同反应，CarE,和P450活动，和每种杀虫剂诱导至少一种解毒酶活性。这些杀虫剂几乎抑制了所有测试的GST的表达，CarE,和P450基因在接触生物测定中，但在饮食生物测定中诱导了这些基因的转录水平。NlGSTD2表达的沉默对接触试验中BPH对氮吡喃胺的敏感性和饮食试验中吡虫啉的敏感性影响最大。NlCE沉默后，接触试验中BPH对杀虫剂的敏感性增加最大的是etofenprox，而饮食测试是氮吡仑。敲除NlCYP408A1导致BPH对杀虫剂的敏感性在接触试验中增加最多的是硝普兰，而饮食测试是吡虫啉。一起来看,这些发现表明，NlGSTD2，NlCE，NlCYP408A1在不同类型杀虫剂对BPH的接触和摄入毒性的解毒中起着不可或缺的作用，这对于制定新的吸虫防治策略具有重要意义。
