Evidence map›Paper›PMID 42109167›Full record

ArticlePest management science2026

Analysis of glutamine synthetase target-site mutations and their role in endowing glufosinate-ammonium resistance.

Aimone Porri, Susee Sudhakar, Matheus M Noguera, Michael Betz, Jens Lerchl, Franck E Dayan, Ingo Meiners, Tino Caldarelli, Jason Norsworthy

Abstract read
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Article in Pest management science, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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4 · The record

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5 · Who and what money

Authors and funding

9 authors.

Aimone Porri *Global Research & Development Agricultural Solutions, BASF SE, Ludwigshafen, Germany.ORCID https://orcid.org/0000-0001-7846-6722
Susee Sudhakar *Department of Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, AR, USA.ORCID https://orcid.org/0009-0004-0300-5605
Matheus M NogueraDepartment of Research Centers, Montana State University, Huntley, MT, USA.
Michael BetzGlobal Research & Development Agricultural Solutions, BASF SE, Ludwigshafen, Germany.
Jens LerchlGlobal Research & Development Agricultural Solutions, BASF SE, Ludwigshafen, Germany.
Franck E DayanDepartment of Agricultural Biology, Colorado State University, Fort Collins, Colorado, USA.ORCID https://orcid.org/0000-0001-6964-2499
Ingo MeinersBASF Agricultural Solutions US LLC, Research Triangle Park, North Carolina, USA.
Tino CaldarelliGlobal Research & Development Agricultural Solutions, BASF SE, Ludwigshafen, Germany.
Jason NorsworthyDepartment of Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, AR, USA.ORCID https://orcid.org/0000-0002-7379-6201

Funding

BASF
6 · The paper itself

Abstract

backgroundGlufosinate-ammonium (GFA) is a non-selective herbicide that inhibits glutamine synthetase (GS), a key enzyme in plant nitrogen metabolism. Although resistance to GFA has been reported in several weed species, confirmed cases of target-site resistance (TSR) via GS mutations remain rare. In Amaranthus palmeri, resistance is usually associated with GS gene amplification and overexpression, while the role of GS point mutations remains unclear. This study investigated GFA resistance in a population lacking GS amplification, and evaluated the functional relevance of putative resistance-conferring GS mutations.

resultsDigital PCR revealed no substantial GS amplification or overexpression in the CCR population. Sequencing identified a glycine-to-aspartic acid substitution at position 255 (G255D) in the chloroplastic GS2.2 isoform, detected in ~80% of CCR plants in heterozygous form. Notably, this mutation was exclusively in untreated plants. In vitro assays showed that GS2.2 G255D retained ~58% of wild-type catalytic activity and was completely insensitive to GFA inhibition. However, ectopic expression of G255D, as well as the homologous Arabidopsis GS2.2 G254D substitution, did not confer GFA tolerance in Arabidopsis. Analysis of GS1.1 variants demonstrated that mutations disrupting GFA binding generally caused severe reductions in catalytic efficiency. Re-evaluation of the previously reported Eleusine indica GS1.1 S59G mutation revealed no meaningful shift in GFA sensitivity.

conclusionsGFA resistance in the CCR population cannot be explained by GS amplification or GS2.2 G255D. These findings underscore the strong structural and functional constraints on GS target-site evolution and suggests that non-target-site mechanisms likely underlie GFA resistance in this population. © 2026 BASF SE and The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Indexed as

AmaranthusAminobutyratesGlutamate-Ammonia LigaseHerbicide ResistanceHerbicidesPlant ProteinsMutationAminobutyratesGlutamate-Ammonia LigaseHerbicidesphosphinothricinPlant ProteinsAmaranthus palmeriEleusine indicaglufosinate resistancegoosegrassmutationpalmer amaranthTSR

Identifiers

PMID42109167
PMCPMC13352219

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.