Huang, X., Xiao, T., Zhao, X., Yang, Z., Sun, Z., Lu, K. (2025). Olfactory perception of trifluralin by GOBP2 decreases the susceptibility of Spodoptera litura to insecticides through modulation of 20E signaling pathway-mediated metabolic detoxification.  J. Hazard. Mater. 500(): 140417.

FBrf0264089

Research paper

Herbicide contamination has emerged as a critical ecological concern due to its persistent environmental accumulation and unintended impacts on non-target species. This study reveals that olfactory exposure to the volatile herbicide trifluralin enhances metabolic detoxification in Spodoptera litura larvae, significantly reducing their susceptibility to indoxacarb and chlorpyrifos. Building on our previous discovery of GOBP2's trifluralin-binding capacity, CRISPR/Cas9-generated GOBP2 knockout (GOBP2[KO]) larvae exhibited compromised loss of cross-tolerance, accompanied by impaired induction of carboxylesterases (COEs) and glutathione S-transferases (GSTs). Mechanistically, trifluralin perception through GOBP2 activated a 20-hydroxyecdysone (20E)-dependent pathway, upregulating both 20E biosynthesis genes and ecdysone receptor (EcR)/ultraspiracle (USP) complexes in wild-type insects. Systemic disruption of this signaling axis via RNAi-mediated EcR/USP co-silencing abolished trifluralin-induced detoxification enzyme activation and restored insecticide vulnerability. Molecular validation through dual-luciferase assays and yeast-one hybrid systems confirmed EcR/USP-mediated transactivation of COE/GSTe genes via conserved response elements. Functional characterization identified GSTe1 and GSTe16 as key effectors, with GSTe16 exhibiting effective metabolic efficiency against indoxacarb (19.25 % degradation) and chlorpyrifos (13.04 % degradation), while GSTe1 showed significant activity toward indoxacarb metabolism (14.96 %) and chlorpyrifos degradation (10.17 %). Genetic evidence from CRISPR/Cas9-ablated S. litura and transgenic Drosophila models further established causal relationships between GSTe expression levels and insecticide tolerance. Our integrated analysis establishes that GOBP2-mediated endocrine signaling constitutes a central axis in trifluralin-induced insecticide tolerance, directly bridging herbicide perception to metabolic resistance through 20E-dependent regulatory cascades.