MicroRNA-Mediated Post-Transcriptional Regulation of Cytochrome P450s

The rapid evolution of metabolic resistance to chemical insecticides and the adaptation to plant allelochemicals in insect pests have become major challenges in global pest management. While the overexpression of cytochrome P450 monooxygenases (P450s) is a well-recognized classic detoxification mechanism, the upstream epigenetic and post-transcriptional regulatory networks governing this process have only recently been elucidated. In this narrative review, the latest research progress on microRNAs (miRNAs) as crucial "fine-tuners" in insect detoxification networks is systematically summarized. The classic regulatory model is highlighted: the induced or constitutive downregulation of specific miRNAs relieves the translational repression of their target P450 genes, thereby contributing to metabolic resistance to major insecticide classes, including neonicotinoids, diamides, and pro-insecticides. Furthermore, the evolutionary recruitment mechanisms of conserved miRNAs in host plant adaptation are explored, and how endocrine signals, such as juvenile hormone (JH) and 20-hydroxyecdysone (20E), synergistically regulate the miRNA-P450 axis is analyzed. The "sponge effect", wherein highly expressed P450 mRNAs act as competitive endogenous RNAs (ceRNAs) to sequester miRNAs, and the consequent physiological trade-offs (fitness costs) resulting from the prioritization of metabolic resources toward the detoxification system are comprehensively discussed. Finally, the current core methodologies for miRNA functional validation are critically evaluated, and the application potential and ecological safety prerequisites of miRNA-based nanobiopesticides for targeted and sustainable pest management are discussed. By integrating mechanistic insights with translational perspectives, this review highlights miRNA-P450 regulatory networks as key determinants of insecticide resistance evolution and as promising targets for developing more precise, environmentally compatible pest-management strategies.