Citrus Research and Education Center, IFAS, University of Florida, Lake Alfred, FL, USA.
School of Agricultural Engineering/Henan Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project/Henan Key Laboratory of Insect Biology in Funiu Mountain, Nanyang Normal University, Nanyang, Henan, China.
Pest Manag Sci. 2018 Mar;74(3):638-647. doi: 10.1002/ps.4747. Epub 2017 Nov 22.
The Asian citrus psyllid, Diaphorina citri Kuwayama, is an important agricultural pest of citrus globally. Foliar application of chemical insecticides is the most widely used option for reducing D. citri populations. Knockdown of glutathione S-transferase (GST) in several insect species leads to increased susceptibility to insecticides; however, information about the detoxifying role of GST genes in D. citri is unavailable.
Via a sequence homology search, we isolated and characterized three DcGST genes (DcGSTd1, DcGSTe1 and DcGSTe2) from D. citri. Phylogenetic analysis grouped DcGSTd1 into the delta class of GST genes, whereas DcGSTe1 and DcGSTe2 were clustered in the epsilon clade. Gene expression analysis revealed that chlorpyrifos treatment increased the mRNA levels of DcGSTe1 and fenpropathrin enhanced the expression level of DcGSTd1, while DcGSTe2 was significantly up-regulated after exposure to thiamethoxam at a dose of 30% lethal concentration (LC30). RNA interference (RNAi) of DcGSTe2 and DcGSTd1 followed by an insecticide bioassay increased the mortalities of thiamethoxam-treated psyllids by 23.0% and fenpropathrin-treated psyllids by 15.0%. In contrast, knockdown of DcGSTe1 did not significantly increase the susceptibility of D. citri to any of these three insecticides. Further, feeding with double-stranded RNA (dsDcGSTe2-d1) interfusion co-silenced DcGSTe2 and DcGSTd1 expression in D. citri, and led to an increase of susceptibility to both fenpropathrin and thiamethoxam.
The findings suggest that DcGSTe2 and DcGSTd1 play unique roles in detoxification of the pesticides thiamethoxam and fenpropathrin. In addition, co-silencing by creating a well-designed dsRNA interfusion against multiple genes was a good RNAi strategy in D. citri. © 2017 Society of Chemical Industry.
亚洲柑橘木虱，Diaphorina citri Kuwayama，是全球柑橘的重要农业害虫。叶面施药是降低 D. citri 种群数量最广泛使用的选择。几种昆虫的谷胱甘肽 S-转移酶 (GST) 的击倒导致对杀虫剂的敏感性增加；然而，关于 GST 基因在 D. citri 中的解毒作用的信息尚不可用。
通过序列同源性搜索，我们从 D. citri 中分离并鉴定了三个 DcGST 基因（DcGSTd1、DcGSTe1 和 DcGSTe2）。系统发生分析将 DcGSTd1 归入 GST 基因的δ类，而 DcGSTe1 和 DcGSTe2 则聚类在ε分支中。基因表达分析表明，毒死蜱处理增加了 DcGSTe1 的 mRNA 水平，而丙溴磷增强了 DcGSTd1 的表达水平，而在用 30%致死浓度 (LC30) 的噻虫嗪处理后，DcGSTe2 显著上调。DcGSTe2 和 DcGSTd1 的 RNA 干扰 (RNAi) 后用杀虫剂进行生物测定，使噻虫嗪处理的木虱死亡率增加了 23.0%，丙溴磷处理的木虱死亡率增加了 15.0%。相比之下，DcGSTe1 的敲低并没有显著增加 D. citri 对这三种杀虫剂中任何一种的敏感性。此外，饲喂双链 RNA (dsDcGSTe2-d1) 融合物共沉默了 D. citri 中的 DcGSTe2 和 DcGSTd1 表达，并导致对丙溴磷和噻虫嗪的敏感性增加。
研究结果表明，DcGSTe2 和 DcGSTd1 在解毒噻虫嗪和丙溴磷农药方面发挥独特作用。此外，通过创建针对多个基因的精心设计的 dsRNA 融合物进行共沉默是 D. citri 中一种良好的 RNAi 策略。 © 2017 化学工业协会。
