Knockdown of TRPV gene Nanchung decreases resistance to the novel pyropene insecticide, afidopyropen, in Bemisia tabaci

Abstract

Insect TRPV is one subfamily of transient receptor potential (TRP) channels, and it is composed of Inactive (Iav) and Nanchung (Nan), the molecular targets of afidopyropen in several sucking insect pests. In this study, we performed successive selection and synergism tests based on previous work. The resistant afidopyropen strain HD-Afi of Bemisia tabaci reached about 86-fold resistance to afidopyropen, and only part of the resistance resulted from detoxification of cytochrome P450 monooxygenases. Then, we cloned and characterized Nan and Iav from B. tabaci (BtNan and BtIav), and found that they were expressed in all stages of development and tissues of adult, and the expression level of BtNan in strains of HD-S and HD-Afi were significantly increased after afidopyropen treatment. Further, expression of BtNan was downregulated after gene silencing, and it resulted in significantly decreased afidopyropen resistance in the strain of HD-Afi. Our data revealed the first evidence that overexpression of the TRPV Nan gene is responsible for causing afidopyropen resistance in B. tabaci, and our results could provide new visions on the function of TRPVs in the development of resistance to pesticide and supply evidence for developing novel strategies of pest management.

Keywords: Afidopyropen; Bemisia tabaci; Insecticide resistance; Nanchung; RNA interference; TRPV channel.