CYP427A1-mediated metabolic resistance to buprofezin and imidacloprid in Nilaparvata lugens from southwestern rice regions of China.

BACKGROUND: Nilaparvata lugens migrates into the inland via the southwestern rice regions of China (SWRR). If pest control fails in this gateway region, it would pose a serious threat to inland rice production. However, due to the historical lack of systematic insecticide resistance monitoring in SWRR, high-level resistance to commonly used insecticides in field populations is continuously and uncontrollably developing. RESULTS: Compared to the Lab-HZ strain, SWRR populations showed significantly higher resistance to buprofezin and imidacloprid. Specifically, the Wangzhou2024 (WZ24) population from Chongqing exhibited a resistance ratio (RR) of 463.21-fold to buprofezin, while the Dehong2024 (DH24) population from Yunnan showed an RR of 758.75-fold to imidacloprid. In these resistant populations, cytochrome P450 monooxygenase (P450) activity increased by 2.5-6.1-fold, and expression of CYP427A1 was up-regulated by 3.8- and 14.4-fold. RNA interference-mediated silencing of CYP427A1 increased mortality of approximately 90% following exposure to buprofezin and imidacloprid. Molecular docking revealed that the binding free energies of CYP427A1 with buprofezin and imidacloprid were -6.1 and -6.3 kcal/mol, respectively, and recombinant CYP427A1 could metabolize both insecticides in vitro. CONCLUSION: This study provides a systematic assessment of insecticide resistance levels in N. lugens from SWRR and demonstrates that CYP427A1-mediated metabolism as a key contributor to high-level resistance to buprofezin and imidacloprid in the populations examined. © 2026 Society of Chemical Industry.