Insight into the Underlying Molecular Toxic Mechanisms of Cyantraniliprole and Broflanilide against Different Targets with Glutathione Transferase Phi8 from <i>Arabidopsis thaliana</i>

As two typical kinds of diamide insecticides, cyantraniliprole and broflanilide are characterized by diverse target receptors and completely distinctive regulation mechanisms. However, the systematical evaluation of oxidative damage on plants induced by cyantraniliprole and broflanilide still remains elusive. In this study, the toxic effects were investigated in the biochemical and physiological aspects using <i>At</i>GSTF8 as a biomarker. First, cyantraniliprole not only brought about much more detrimental impacts on the growth status of plant seedlings but also resulted in a significant upregulation of <i>At</i>GSTF8 gene expression compared to broflanilide. Then, the glutathione <i>S</i>-transferase activities of <i>At</i>GSTF8 decreased greatly with treatment of these two diamide insecticides. Moreover, biolayer interferometry analysis confirmed the interactions of both cyantraniliprole and broflanilide with <i>At</i>GSTF8, especially for cyantraniliprole with stronger binding affinity, which conformed to the molecular docking results. At last, even more adverse effects on the structural conformations of <i>At</i>GSTF8 upon binding with cyantraniliprole were observed.