Iso-seq profiling of the alternative splicing provides insights into dose-dependent potentiation of sublethal effects in Thrips palmi

Sublethal insecticide exposure drives rapid environmental adaptation through transcriptional diversification, yet its molecular mechanisms remain poorly characterized. Here, we integrated Iso-seq full-length transcriptomics and analyses to demonstrate that exposure to sublethal concentrations of spinetoram induce dose-dependent response in Thrips palmi Karny, which is a representative vegetable pest that poses a severe threat and has rampant insecticide resistance. Notably, the alternative splicing (AS) and alternative polyadenylation demonstrated the highest levels under exposure to the highest sublethal concentrations (LC₄₀ treatment). Most novel isoforms and fusion genes were also identified in response to the stress of higher sublethal concentrations. The significant enrichment of differential ASs following sublethal concentration exposure was annotated as cytochrome P450s, ATP-binding cassette transporters and cytochrome P450 reductase, all of which are associated with detoxification pathways and stress tolerance. This work elucidates how transcriptional plasticity facilitates rapid pest adaptation to sublethal stress, advocating for the integration of novel biomarkers into evolutionary toxicology frameworks to enhance insecticide resistance management.