Recently, Prof. Zhang Youjun’s team of Institute of Vegetables and Flowers，Chinese Academy of Agricultural Sciences, revealed that the trans-regulation of a cytochrome P450 that confers resistance to insecticides in the whitefly. These results provide new mechanistic insights into the regulation of xenobiotic responses in insects. Related paper entitled MAPK-directed activation of the whitefly transcription factor CREB leads to P450-mediated imidacloprid resistance was published in PNAS on April 23, 2020.

The evolution of insect resistance to pesticides poses a continuing threat to agriculture and human health. While much is known about the proximate molecular and biochemical mechanisms that confer resistance, far less is known about the regulation of the specific genes/gene families involved, particularly by trans-acting factors such as signal-regulated transcription factors.

In this study, researchers resolve in fine detail the trans-regulation of CYP6CM1, a cytochrome P450 that confers resistance to neonicotinoid insecticides in the whitefly, Bemisia tabaci, by the mitogen-activated protein kinase (MAPK)-directed activation of the transcription factor cAMP-response element binding protein (CREB). Investigation of potential trans-acting factors using in vitro and in vivo assays demonstrated that the bZIP transcription factor CREB directly regulates CYP6CM1 expression by binding to a cAMP-response element (CRE)-like site in the promoter of this gene. CREB is overexpressed in the resistant strain and inhibitor, luciferase, and RNA interference assays revealed that a signaling pathway of MAPKs mediates the activation of CREB, and thus the increased expression of CYP6CM1, by phosphorylation-mediated signal transduction. Collectively, these results provide new mechanistic insights into the regulation of xenobiotic responses in insects, and implicate both the MAPK signaling pathway and a novel transcription factor in the development of pesticide resistance.

This research was supported by the National Natural Science Foundation of China (31420103919 and 31601664), National Key R&D Program of China (2016YFD0200500), China Agriculture Research System (CARS-24-C-02), the Beijing Key Laboratory for Pest Control and Sustainable Cultivation of Vegetables and the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences (CAAS-ASTIP-IVFCAAS). More information can be found through the link:

http://www.pnas.org/content/117/19/10246

By Yang Xin (yangxin@caas.cn)