Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.
College of Life Sciences, Nankai University, Tianjin, 300071, China.
Insect Biochem Mol Biol. 2018 Aug;99:17-26. doi: 10.1016/j.ibmb.2018.05.007. Epub 2018 May 26.
Flonicamid is a selective insecticide for the control of sap-sucking insects; it exerts toxic effects by inhibiting insect feeding. However, its molecular target remains elusive. In this study, we functionally characterized NlKir1 channels of the brown planthopper (Nilaparvata lugens) in HEK293 cells. Homomeric NlKir1 channels generated inward-rectifying K currents. Flonicamid inhibited NlKir1 channels at nanomolar concentrations. Furthermore, flonicamid inhibited honeydew and salivary secretions of planthoppers, and reduced the renal excretion of female mosquitoes in a dose-dependent manner. The inhibitory effect of flonicamid on fluid secretion of isolated Malpighian tubules from Culex pipiens pullens was comparable to that of the selective Kir1 inhibitor. The observed physiological alterations by flonicamid are likely mediated by Kir1 channels and could lead to the disruption of feeding behaviors and eventually lethality. Our study establishes the Kir1 channel as the target of flonicamid and provided new insights into the mode of action of flonicamid.
氟啶虫酰胺是一种用于防治刺吸式昆虫的选择性杀虫剂；它通过抑制昆虫取食来发挥毒性作用。然而，其分子靶标仍然难以捉摸。在这项研究中，我们在 HEK293 细胞中对褐飞虱（Nilaparvata lugens）的 NlKir1 通道进行了功能表征。同型 NlKir1 通道产生内向整流 K 电流。氟啶虫酰胺以纳摩尔浓度抑制 NlKir1 通道。此外，氟啶虫酰胺以剂量依赖的方式抑制了粉虱的蜜露和唾液分泌，并减少了雌性蚊子的肾脏排泄。氟啶虫酰胺对来自库蚊（Culex pipiens pullens）的离体马氏管的流体分泌的抑制作用与选择性 Kir1 抑制剂相当。氟啶虫酰胺引起的生理变化可能是由 Kir1 通道介导的，这可能导致摄食行为的破坏，并最终导致死亡。我们的研究确立了 Kir1 通道是氟啶虫酰胺的靶标，并为氟啶虫酰胺的作用模式提供了新的见解。
