Clothianidin resistance in field populations of Nilaparvata lugens Stål

The brown planthopper (Nilaparvata lugens Stål, BPH), a major rice pest, has evolved resistance to multiple insecticides, undermining chemical control and threatening rice production. Monitoring resistance dynamics, elucidating mechanisms, and informing management are therefore essential. In this study, we evaluated resistance in nine N. lugens field populations collected from Hubei and Hunan Provinces in 2024 to clothianidin. N. lugens field populations exhibited high-level resistance to clothianidin. Detoxification enzyme activity assays and synergist tests indicated that changes in detoxification enzyme activity cause alterations in the susceptibility of N. lugens field populations to clothianidin. qRT-PCR analyses demonstrated significant upregulation of CYP4C62, CYP4C76, CYP4CE1, CYP425B1, CYP6CS1, CYP6CW1 in most populations. NlCarE19 was consistently overexpressed across all nine populations, indicating a conserved association with insecticide resistance. RNAi-mediated silencing of each upregulated P450 gene or NlCarE19 significantly increased clothianidin toxicity, thereby indicating their functional contributions to clothianidin resistance in N. lugens. And the molecular docking revealed that NlCarE19 exhibit higher binding affinity for clothianidin. The findings provide an evidence base for optimizing resistance management and inform integrated resistance management strategies to slow resistance evolution and sustain rice protection.