LAUSR

BACKGRAOUD Non-target-site resistance (NTSR) to herbicide is a serious threat to global agriculture. Though the metabolic resistance was the dominant mechanism of NTSR, the molecular mechanism is not yet well-characterized. This study aimed to uncover the likely metabolism-related genes in Beckmannia syzigachne (American sloughgrass) resistant to fenoxaprop-p-ethyl. RESULTS UPLC-MS-MS experiment showed that the resistant American sloughgrass biotype (R, SD-04-SS) showed enhanced degradation of this herbicide compared to the susceptible biotype (S, SD-12). R and S biotype were harvested at the 24 hour after fenoxaprop-p-ethyl treatment to conduct RNA sequencing (RNA-Seq) analysis to investigate the likely fenoxaprop-p-ethyl metabolic genes. The RNA-Seq libraries yield 417,969,980 clean reads. The de novo assembly generated 115,112 unigenes, in which 57906 unigenes were annotated. Finally, we identified 273 cytochrome P450s, 178 oxidase, 47 GSTs, 166 GTs and 180 ABC transporter genes to determine the likely fenoxaprop-p-ethyl metabolism-related genes in R biotype. Twelve overlapping up-regulated genes in R biotype (fenoxaprop-p-ethyl-treated R/non-treated R, fenoxaprop-p-ethyl-treated R/fenoxaprop-p-ethyl-treated S) were identified by RNA-Seq and the results were validated using qRT-PCR. Ten were identified as fenoxaprop-p-ethyl metabolism-related genes including three P450s (homology to CYP71D7, CYP99A2, and CYP71D10), one GSTs (homology to GSTF1), two GTs (homology to UGT90A1 and UGT83A1) and four oxidase genes. CONCLUSION This work demonstrates that the NTSR mechanism by means of enhanced detoxification of fenoxaprop-p-ethyl in American sloughgrass is very likely driven by the herbicide metabolism related genes. The RNA-Seq data presented here provide a valuable resource for understanding the molecular mechanism of NTSR in American sloughgrass. This article is protected by copyright. All rights reserved.