Glycosyltransferase genes are associated with resistance to cyhalofop-butyl in a Chinese Echinochloa crus-galli population

BACKGROUND: Echinochloa crus-galli is the most troublesome and widespread weed of most rice-growing regions of the world. Cyhalofop-butyl, a herbicide within the acetyl-CoA carboxylase (ACCase) chemical group, has been extensively used to control barnyardgrass in rice. The repeated exposure to cyhalofop-butyl has led to resistance evolution in E. crus-galli populations. RESULTS: In this study, we identified a population of E. crus-galli (R-HN) in a rice field in Hunan, China, that developed resistance to cyhalofop-butyl at 4.49-fold the recommended field dose. No known target mutation was detected in the ACCase gene of the R-HN population by ACCase sequencing compared to sensitive populations. Both cytochrome P450 (CYP450) and glutathione S-transferase (GST) inhibitors could not significantly reverse the resistance to cyhalofop-butyl. The nontarget-site resistance (NTSR) mechanism was investigated by transcriptome sequencing. Validation of the screened candidate genes by quantitative real-time (qRT)-PCR revealed that six glycosyltransferases (GTs) and four ATP-binding cassette (ABC) transporter genes were consistently upregulated in the R-HN population. Five GTs and one ABC transporter genes were constitutively upregulated after cyhalofop-butyl treatment in the R-HN population. Molecular docking results showed that the significant binding energy of GT79, GT75L6 and GT74E among all candidate genes. CONCLUSION: Thus, the GT genes appear to be directly implicated in NTSR to cyhalofop-butyl in the R-HN populations through metabolic enhancement, but their functional characterization needs to be studied. (c) 2024 Society of Chemical Industry.