Methyl Eugenol Binds Recombinant Gamma-Aminobutyric Acid Receptor-Associated Protein from the Western Flower Thrips Frankliniella occidentalis.

Li Wang, Maoxi Huang, Zilin Wu, Min Huang, Yunlong Yan, Baoan Song, Xiangyang Li, Qing X Li

Journal of agricultural and food chemistry 2022 Apr 27

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The western flower thrips (Frankliniella occidentalis) is a major pest insect in agriculture. However, few insecticides are effective for their control. The recombinant gamma-aminobutyric acid receptor-associated protein (rGABARAP) was examined as a potential target of the monoterpenoids responsible for their insecticidal activities. The insecticidal activity of anethole, linalool, and methyl eugenol (ME) was evaluated in the laboratory. The half-maximum lethal concentration (LC50) of ME against second-instar nymphs of F. occidentalis was 5.5 mg/L using membrane and leaf immersion methods, while that of spinosyn A was 1.0 mg/L. The dissociation constants of ME binding to rGABARAP were 1.30 and 4.22 μmol/L, respectively, according to microscale thermophoresis (MST) and isothermal titration calorimetry (ITC) measurements. A molecular docking study showed interactions between ME and Tyr174 via π-π stacking. The MST and ITC experiments showed loss of specific binding between ME and the rGABARAPY174A mutant. Therefore, Tyr174 is a key amino acid residue of rGABARAP involving ME binding. The results revealed GABARAP as a potential target for the development of monoterpenoid insecticides.

Citation

Li Wang, Maoxi Huang, Zilin Wu, Min Huang, Yunlong Yan, Baoan Song, Xiangyang Li, Qing X Li. Methyl Eugenol Binds Recombinant Gamma-Aminobutyric Acid Receptor-Associated Protein from the Western Flower Thrips Frankliniella occidentalis. Journal of agricultural and food chemistry. 2022 Apr 27;70(16):4871-4880