Confirmation of glufosinate-resistant Palmer amaranth and response to other herbicides

Priess, Grant L.; Norsworthy, Jason K.; Godara, Navdeep; Mauromoustakos, Andy; Butts, Thomas R.; Roberts, Trenton L.; Barber, Tom

doi:10.1017/wet.2022.21

Cited by 22 publications

(24 citation statements)

References 18 publications

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“…The susceptible accessions showed no increase in GS2 expression. In a dose-response experiment, accession Glu-R1 showed 24-fold glufosinate resistance (Priess et al 2022). The resistance fold obtained by Priess et al (2022) and the relative GS2 expression obtained in this study for accession Glu-R1 are similar, suggesting that high copy number and expression may confer high resistance.…”

Section: Glutamine Synthetase Sequencing Relative Copy Number and Exp...mentioning

confidence: 99%

“…In a dose-response experiment, accession Glu-R1 showed 24-fold glufosinate resistance (Priess et al 2022). The resistance fold obtained by Priess et al (2022) and the relative GS2 expression obtained in this study for accession Glu-R1 are similar, suggesting that high copy number and expression may confer high resistance. Therefore, gene amplification and overexpression of GS2 enzyme is likely the mechanism conferring glufosinate resistance in the A. palmeri accessions investigated in this study.…”

Section: Glutamine Synthetase Sequencing Relative Copy Number and Exp...mentioning

confidence: 99%

“…Husnot], perennial ryegrass (Lolium perenne L.), rigid ryegrass (Lolium rigidum Gaudin), and Palmer amaranth (Amaranthus palmeri S. Watson). Amaranthus palmeri is the first and only broadleaf weed resistant to glufosinate (Avila-Garcia and Mallory-Smith 2011; Ghanizadeh et al 2015;Heap 2022b;Jalaludin et al 2010;Priess et al 2022;Seng et al 2010;Travlos et al 2018).…”

Section: Introductionmentioning

confidence: 99%

“…With this knowledge, scientists can design and apply proper strategies to limit the spread of resistance (Norsworthy et al 2012). Glufosinate resistance was characterized in three A. palmeri accessions from Arkansas by Priess et al (2022), and a high resistance level was observed in one of these accessions (resistance/susceptibility ratio = 24). In this study, this highly glufosinate-resistant accession was further used to investigate the mechanism conferring resistance to glufosinate.…”

Section: Introductionmentioning

confidence: 99%

“…In 2019 and 2020, Arkansas farmers from Crittenden and Mississippi counties noticed that glufosinate applications failed to control A. palmeri plants. Seeds from these fields were collected, and glufosinate resistance was confirmed through dose–response experiments (Priess et al 2022). In addition to glufosinate, A. palmeri is resistant to herbicides targeting eight other sites of action, which makes this weed extremely challenging to control (Heap 2022b).…”

Section: Introductionmentioning

confidence: 99%

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Unraveling the mechanism of resistance in a glufosinate-resistant Palmer amaranth (Amaranthus palmeri) accession

Carvalho-Moore

Norsworthy²,

González-Torralva

et al. 2022

Weed Sci

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Glufosinate resistance in Palmer amaranth (Amaranthus palmeri S. Watson] was recently detected in three accessions from Arkansas. Amaranthus palmeri is the first and only broadleaf weed species resistant to this herbicide, and the resistance mechanism is still unclear. A previous study characterized the glufosinate resistance level in the accessions from Arkansas. A highly glufosinate-resistant accession was further used to investigate the mechanism conferring glufosinate resistance in A. palmeri. Experiments were designed to sequence the herbicide target enzyme cytosolic and chloroplastic glutamine synthetase isoforms (GS1 and GS2, respectively) and quantify copy number and expression. Absorption, translocation, and metabolism of glufosinate using the carbon-14-labeled herbicide were also evaluated in resistant and susceptible accessions. The glufosinate-resistant accession had an increase in copy number and expression of GS2 compared to susceptible plants. All accessions showed only one GS1 copy and no differences in expression. No mutations were identified in GS1 or GS2. Absorption (54 to 60%) and metabolism (13 to 21%) were not different between the glufosinate-resistant and susceptible accessions. Most residues of glufosinate (94 to 98%) were present in the treated leaf. Glufosinate translocation to tissues above the treated leaf and in the roots was not different among accessions. However, glufosinate translocation to tissues below the treated leaf (not including roots) was greater in the resistant A. palmeri (2%) compared to the susceptible (less than 1%) accessions. The findings of this paper strongly indicate that gene amplification and increased expression of the chloroplastic glutamine synthetase enzyme are the mechanisms conferring glufosinate resistance in the A. palmeri accession investigated. Thus far, no additional resistance mechanism was observed, but further investigations are ongoing.

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Section: Glutamine Synthetase Sequencing Relative Copy Number and Exp...mentioning

confidence: 99%

Section: Glutamine Synthetase Sequencing Relative Copy Number and Exp...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Unraveling the mechanism of resistance in a glufosinate-resistant Palmer amaranth (Amaranthus palmeri) accession

Carvalho-Moore

Norsworthy²,

González-Torralva

et al. 2022

Weed Sci

Self Cite

View full text Add to dashboard Cite

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Biological effects on Palmer amaranth surviving glufosinate

Jones

León

Everman

2022

Agrosystems Geosci & Env

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Palmer amaranth (Amaranthus palmeri S. Watson) is a difficult weed to manage due to competitive growth, fecundity, and evolved herbicide resistance. Limited information exist on the fecundity of vegetative stage Palmer amaranth surviving glufosinate applied at different timings. In addition, research has not investigated the germination or glufosinate susceptibility of the offspring from these surviving plants. Field experiments were conducted across three locations in 2019 to determine (a) the fecundity of Palmer amaranth plants surviving glufosinate applied at different vegetative growth stages, and (b) if the offspring from the surviving plants exhibited differential germination and susceptibility to glufosinate. Palmer amaranth was treated at three different vegetative sizes (5 cm, 7-10 cm, > 10 cm) and orthogonal combinations of these application timings. The application timings corresponded to early-, mid-and late-postemergence applications. Palmer amaranth plants surviving the mid-, late-, and the mid postemergence followed by late postemergence glufosinate application were fecund. Palmer amaranth plants surviving the mid postemergence followed by late postemergence application produced less seed than the plants surviving the mid postemergence and late postemergence application. Palmer amaranth was controlled with other glufosinate applications resulting in no seed production. Germination was affected across location and glufosinate treatments, but no clear trend/pattern was observed. The offspring from Palmer amaranth plants surviving glufosinate applications were controlled by all glufosinate rates tested. These experiments provide evidence that Palmer amaranth surviving glufosinate in the vegetative stages may remain fecund, but fecundity can vary with application timing. No measurable effect on the offspring germination or susceptibility to glufosinate was apparent.

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Late postemergence glufosinate‐based programs for glyphosate‐resistant Palmer amaranth control in dicamba/glufosinate/glyphosate‐resistant soybean

Kumar

Aulakh

et al. 2023

Agrosystems Geosci & Env

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Glyphosate‐resistant (GR) Palmer amaranth (Amaranthus palmeri S. Watson) is widespread in the Central Great Plains. Introduction of newly developed dicamba/glufosinate/glyphosate (DGG)‐resistant soybean varieties allows postemergence (POST) applications of dicamba and glufosinate for in‐season control of GR Palmer amaranth. Limited information exists on the effectiveness of glufosinate applied late‐POST for tall (70–90 cm) GR Palmer amaranth control in DGG‐resistant soybean. The objectives of this study were to (1) determine the effectiveness of late‐POST glufosinate‐based programs for GR Palmer amaranth control, and (2) determine the impact of those programs on soybeans grain yields. Ten glufosinate‐based programs were tested in a field study at Kansas State University Agricultural Research Center near Hays, Kansas. Results indicated that single (655 or 737 g ha−1) and all sequential (594 followed by [fb] 594, 655 fb 594, and 737 fb 594 g ha−1) applications (7‐days apart) of glufosinate provided 87%–93% control of GR Palmer amaranth 28 days after last POST (DALPOST). Palmer amaranth control with single late‐POST application of glufosinate (594 g ha−1) or glufosinate plus S‐metolachlor did not exceed 84% at 28 DALPOST. Majority of the evaluated programs reduced shoot dry weights of GR Palmer amaranth by 83%–91%. The least control (11%) and shoot dry weight reduction (33%) of GR Palmer amaranth were observed with glyphosate fb glyphosate. Glufosinate‐based programs resulted in soybean grain yield of 626–701 kg ha−1. These results conclude that glufosinate applied late‐POST may provide effective control of tall GR Palmer amaranth in DGG‐resistant soybeans.

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Confirmation of glufosinate-resistant Palmer amaranth and response to other herbicides

Cited by 22 publications

References 18 publications

Unraveling the mechanism of resistance in a glufosinate-resistant Palmer amaranth (Amaranthus palmeri) accession

Unraveling the mechanism of resistance in a glufosinate-resistant Palmer amaranth (Amaranthus palmeri) accession

Biological effects on Palmer amaranth surviving glufosinate

Late postemergence glufosinate‐based programs for glyphosate‐resistant Palmer amaranth control in dicamba/glufosinate/glyphosate‐resistant soybean

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