Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a major pest of soybean fields. While high-temperature stress induced by global warming can initially suppress aphid populations, these pests may eventually adapt, leading to more severe infestations and crop damage. Heat shock proteins (HSPs), which are upregulated in response to heat stress to protect aphid development, also confer tolerance to other abiotic stressors, including insecticides. To investigate the role of HSPs in insecticide resistance in A. glycines, we analyzed the expression profiles of three AgHsp90 genes (AgHsp75, AgHsp83, and AgGrp94) following exposure to high temperatures and insecticides. Functional validation was performed using RNA interference (RNAi) to silence AgHsp90 genes. Our results demonstrated that AgHsp90 genes were significantly upregulated under both heat and insecticide stress conditions. Furthermore, after feeding on dsRNA of AgHsp90 genes, mortality rates of A. glycines significantly increased when exposed to imidacloprid and lambda-cyhalothrin. This study provides evidence that AgHsp90 genes play a crucial role in mediating thermal tolerance and insecticide resistance in A. glycines.

Common ragweed, Ambrosia artemisiifolia L., a noxious invasive plant, produces novel secondary metabolites. However, it attracts soybean aphid, Aphis glycines, a significant pest of soybean, to feed on it. Elucidating the molecular mechanisms of A. glycines adaptation to A. artemisiifolia may help identify target genes useful for pest management. High-throughput transcriptome sequencing identified 4250 differentially expressed genes (DEGs), with 2399 upregulated and 1851 downregulated. KEGG pathway enrichment analysis suggested that these DEGs were significantly involved in core detoxification-related pathways, including metabolism of xenobiotics by cytochrome P450, drug metabolism, ascorbate and aldarate metabolism, and pentose and glucuronate interconversions. Further analysis revealed significant upregulation of 17 UDP-glycosyltransferase (UGT) genes, with AgUGT342B2, AgUGT343B2, AgUGT344J2, AgUGT344L2, and AgUGT344N2 showing 6.34-, 6.22-, 2.14-, 3.98-, and 7.49-fold higher expression, respectively, than in A. glycines fed on soybean. Bioassays demonstrated that A. glycines reared on A. artemisiifolia exhibited significantly reduced sensitivity to three common insecticides, imidacloprid, thiamethoxam, and lambda-cyhalothrin, with LC₅₀ values increasing by 5.8-fold, 2.8-fold, and 3.6-foldhigher, respectively, than those reared on soybean. These findings indicate that feeding on A. artemisiifolia induces UGT gene family upregulation in A. glycines, conferring cross-resistance to multiple insecticide classes. This study reveals a molecular mechanism linking host adaptation to insecticide resistance, highlighting the ecological and evolutionary consequences of invasive plant-herbivore interactions.