Detection of the Trp-2027-Cys Mutation in Fluazifop-P-butyl–resistant Itchgrass (Rottboellia cochinchinensis) using High-Resolution Melting Analysis (HRMA)

Abstract

Itchgrass [Rottboellia cochinchinensis (Lour.) Clayton] is recognized as one of the most noxious and troublesome annual weeds in tropical and subtropical regions. Acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides have been frequently used for managing R. cochinchinensis POST in a variety of crops, resulting in evolved resistance to these herbicides. Recently, resistance to fluazifop-P-butyl has been demonstrated for this weed, as the result of a G-to-C single-nucleotide polymorphism (SNP) that leads to the Trp-2027-Cys substitution in the ACCase enzyme. This study was conducted to develop a high-resolution melting analysis (HRMA) for the detection of the mutation underlying the Trp-2027-Cys substitution. The HRMA assay allowed differentiating between fluazifop-P-butyl-resistant (C mutant) and susceptible (G wild type) R. cochinchinensis plants. HRMA accuracy was confirmed with DNA sequencing of the target-site mutation, and no false positives or negatives were observed. Our results illustrated how HRMA is effective detecting the Trp-2027-Cys substitution in an R. cochinchinensis resistance, and how this technique can be of great value for developing high-throughput programs for monitoring evolution and dispersion of target site-based herbicide resistance at large scales.

Cyhalofop‐butyl resistance conferred by a novel Trp‐2027‐Leu mutation of acetyl‐CoA carboxylase and enhanced metabolism in Leptochloa chinensis

“…To date, only two AASs including Trp-to-Cys and Trp-to-Ser at codon 2027 have been reported to confer herbicide resistance. [38][39][40][41] To our best knowledge, this study reports for the first time the Trp-2027-Leu substitution of ACCase conferring cyhalofop-butyl resistance in weed species. The rarity of Trp-2027-Leu of ACCase may be partially due to its possible adverse pleiotropic effects on plant growth by changing enzyme functionality.…”

“…In this current study, comparison of the ACCase genes from both biotypes identified a Trp‐2027‐Leu substitution in each R individual, but it was detected only in their ACCase1,2 copies. To date, only two AASs including Trp‐to‐Cys and Trp‐to‐Ser at codon 2027 have been reported to confer herbicide resistance 38–41 . To our best knowledge, this study reports for the first time the Trp‐2027‐Leu substitution of ACCase conferring cyhalofop‐butyl resistance in weed species.…”

A novel triple amino acid substitution in the EPSPS found in a high‐level glyphosate‐resistant Amaranthus hybridus population from Argentina

“…Molecular screening of TAP‐IVS triple substitution (T102I + A103V + P106S) in population A was carried out using a high‐resolution melting analysis (HRMA) approach . Primers and the qPCR program were identical to those used in the epsps copy number study, using 1 μL of single‐seed DNA as template.…”

Mechanism of Resistance to Pyroxsulam in Multiple-Resistant Alopecurus myosuroides from China

“…In this study, the AH93 A. myosuroides population could survive the pinoxaden application at 4× the field rate (240 g ha −1 ) and the Trp-2027-Cys and Arg-2088-Cys amino acid mutations were identified. The Trp-2027-Cys mutation has been reported in many grass weed species, such as Digitaria insularis [21] and Rottboellia cochinchinensis [22]. A. myosuroides with Trp-2027-Cys mutation from France could withstand pinoxaden application in the field rate (60 g ha −1 ) and showed cross-resistance to fenoxaprop and clodinafop [23].…”