Chao He, Ying Zhang, Zelu Yang, Jinjin Liang, Xuegao Wei, Rong Zhang, Buli Fu, Peipan Gong, Zhaojiang Guo, Shaoli Wang, Qingjun Wu, Wen Xie, Xuguo Zhou, Youjun Zhang, Xin Yang
This study provides a comprehensive overview of the P450 gene family, facilitating a better understanding of its evolution and potential functions in B. tabaci B/MEAM1 and Q/MED. More importantly, our results suggest that CYP6CX4 may contribute to clothianidin resistance in Q/MED but not in B/MEAM1. These findings improve our understanding of P450-mediated resistance and provide useful targets for resistance monitoring and management in B. tabaci. © 2026 Society of Chemical Industry.
BACKGROUND: Bemisia tabaci is a globally invasive agricultural pest. The B. tabaci Q/MED has rapidly replaced B/MEAM1, largely due to Q/MED's high resistance to neonicotinoid insecticides. Although cytochrome P450s (P450s) are major detoxification enzymes involved in insecticide resistance, the genome-wide identification and functional contributions to differential clothianidin resistance between B/MEAM1 and Q/MED remain poorly understood.
RESULTS: A total of 129 P450 genes were identified in both B/MEAM1 and Q/MED genomes, with marked expansions observed in clan 3 and clan 4. Comparative chromosomal mapping of P450 genes revealed a largely conserved genomic organization between B/MEAM1 and Q/MED, together with lineage-specific rearrangements. Transcriptional profiling across developmental stages identified a distinct stage-specific high expression cluster in post-embryonic stages, especially in Q/MED. Among the high expression genes, CYP6DV4 was up-regulated in clothianidin-resistant populations of both B/MEAM1 and Q/MED B. tabaci and CYP6CX4 was consistently overexpressed specifically in two Q/MED clothianidin-resistant populations. Crucially, functional characterisation revealed that CYP6CX4 confers resistance in vivo by RNA interference and can metabolise clothianidin into clothianidin-guanidine in vitro via Ultra-Performance Liquid Chromatography-Mass Spectrometry (UPLC/MS) analysis.
CONCLUSION: This study provides a comprehensive overview of the P450 gene family, facilitating a better understanding of its evolution and potential functions in B. tabaci B/MEAM1 and Q/MED. More importantly, our results suggest that CYP6CX4 may contribute to clothianidin resistance in Q/MED but not in B/MEAM1. These findings improve our understanding of P450-mediated resistance and provide useful targets for resistance monitoring and management in B. tabaci. © 2026 Society of Chemical Industry.