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EPSPS Gene Amplification Primarily Confers Glyphosate Resistance among Arkansas Palmer amaranth (Amaranthus palmeri) Populations

  • Shilpa Singh (a1), Vijay Singh (a2), Amy Lawton-Rauh (a3), Muthukumar V. Bagavathiannan (a4) and Nilda Roma-Burgos (a5)...


Research was conducted to determine whether resistance to glyphosate among Palmer amaranth (Amaranthus palmeri S. Watson) populations within the U.S. state of Arkansas was due solely to increased EPSPS gene copy number and whether gene copy number is correlated with resistance level to glyphosate. One hundred and fifteen A. palmeri accessions were treated with 840 g ae ha−1 glyphosate. Twenty of these accessions, selected to represent a broad range of responses to glyphosate, underwent further testing. Seven of the accessions were controlled with this dose; the rest were resistant. The effective dose to cause 50% injury (ED50) for susceptible accessions ranged from 28 to 207 g ha−1. The glyphosate-resistant (GR) accessions had ED50 values ranging from 494 to 1,355 g ha−1, a 3- to 48-fold resistance level compared with the susceptible standard (SS). The 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene relative copy number was determined for 20 accessions, 4 plants accession−1. Resistant plants from five GR accessions (38% of resistant plants tested) did not have increased EPSPS gene copies. Resistant plants from the remaining eight GR accessions (62% of resistant plants tested) had 19 to 224 more EPSPS gene copies than the SS. Among the accessions tested, injury declined 4% with every additional EPSPS copy. ED50 values were directly correlated with EPSPS copy number. The highly resistant accession MIS11-B had an ED50 of 1,355 g ha−1 and 150 gene copies. Partial sequences of EPSPS from GR accessions without EPSPS amplification did not contain any of the known resistance-conferring mutations. Nearly 40% of GR accessions putatively harbor non–target site resistance mechanisms. Therefore, elevated EPSPS gene copy number is associated with glyphosate resistance among A. palmeri from Arkansas.


Corresponding author

Author for correspondence: Nilda Roma-Burgos, Cell and Molecular Biology Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR 72701. (Email:


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Baerson, SR, Rodriguez, DJ, Tran, M, Feng, Y, Biest, NA, Dill, GM (2002) Glyphosate-resistant goosegrass: identification of a mutation in the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase. Plant Physiol 129, 12651275.
Bradshaw, LD, Padgette, SR, Kimball, SL, Wells, BH (1997) Perspectives on glyphosate resistance. Weed Technol 11, 189198.
Burgos, NR, Tranel, PJ, Streibig, JC, Davis, VM, Shaner, D, Norsworthy, JK, Ritz, C (2013) Confirmation of resistance to herbicides and evaluation of resistance levels. Weed Sci 61, 420.
Chahal, PS, Varanasi, VK, Jugulam, M, Jhala, AJ (2017) Glyphosate-resistant Palmer amaranth (Amaranthus palmeri) in Nebraska: confirmation, EPSPS gene amplification, and response to POST corn and soybean herbicides. Weed Technol 31, 8093.
Chandi, A, Milla-Lewis, SR, Giacomini, D, Westra, P, Preston, C, Jordan, DL, York, AC, Burton, JD, Whitaker, JR (2012) Inheritance of evolved glyphosate resistance in a North Carolina Palmer amaranth (Amaranthus palmeri) biotype. Int J Agron 2012, 17.
Chatham, LA, Bradley, KW, Kruger, GR, Martin, JR, Owen, MD, Peterson, DE, Mithila, J, Tranel, PJ (2015) A multistate study of the association between glyphosate resistance and EPSPS gene amplification in waterhemp (Amaranthus tuberculatus). Weed Sci 63, 569577.
Chen, J, Huang, H, Zhang, C, Wei, S, Huang, Z, Chen, J, Wang, X (2015) Mutations and amplification of EPSPS gene confer resistance to glyphosate in goosegrass (Eleusine indica). Planta 242, 859868.
Dinelli, G, Marotti, I, Bonetti, A, Catizone, P, Urbano, JM, Barnes, J (2008) Physiological and molecular bases of glyphosate resistance in Conyza bonariensis biotypes from Spain. Weed Res 48, 257265.
Doyle, JJ, Doyle, JS (1990) A rapid DNA isolation procedure for small quantities of fresh leaf tissue. Phytochem Bull 19, 1115.
Duke, SO, Powles, SB (2008) Glyphosate: a once-in-a-century herbicide. Pest Manag Sci 64, 319325.
Eichholtz, DA, Scott, GC, Murthy, KG, inventors; Monsanto Company, assignee (2001) May 1. Modified gene encoding glyphosate-tolerant 5-enolpruvyl-3-phosphoshikimate synthase. US patent 427 6, 225–114.
Feng, PC, Tran, M, Chiu, T, Sammons, RD, Heck, GR, CaJacob, CA (2004) Investigation into GR horseweed (Conyza canadensis): retention, uptake, translocation and metabolism. Weed Sci 52, 498505.
Fernández-Moreno, PT, Alcantara-de la Cruz, R, Cruz-Hipólito, HE, Rojano-Delgado, AM, Travlos, I, De Prado, R (2016) Non-target site tolerance mechanisms describe tolerance to glyphosate in Avena sterilis . Front Plant Sci 7, 1220.
Fernández-Moreno, PT, Bastida, F, De Prado, R (2017) Evidence, mechanism and alternative chemical seedbank-level control of glyphosate resistance of a rigid ryegrass (Lolium rigidum) biotype from southern Spain. Front Plant Sci 8, 450.
Gaines, TA, Shaner, DL, Ward, SM, Leach, JE, Preston, C, Westra, P (2011) Mechanism of resistance of evolved glyphosate-resistant Palmer amaranth (Amaranthus palmeri). J Agric Food Chem 59, 58865889.
Gaines, TA, Zhang, W, Wang, D, Bukun, B, Chisholm, ST, Shaner, DL, Nissen, SJ, Patzoldt, WL, Tranel, PJ, Culpepper, AS, Grey, TL, Webster, TM, Vencill, WK, Sammons, RD, Jiang, J, Preston, C, Leach, JE, Westra, P (2010) Gene amplification confers glyphosate resistance in Amaranthus palmeri . Proc Natl Acad Sci USA 107, 10291034.
Ge, X, d’Avignon, DA, Ackerman, JJ, Collavo, A, Sattin, M, Ostrander, EL, Hall, EL, Sammons, RD, Preston, C (2012) Vacuolar glyphosate-sequestration correlates with glyphosate resistance in ryegrass (Lolium spp.) from Australia, South America, and Europe: a 31P NMR investigation. J Agric Food Chem 60, 12431250.
Hall, TA (1999) BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucleic Acids Symp Ser 41, 9598.
Heap, I (2017). The International Survey of Herbicide Resistant Weeds. Accessed: February 6, 2017.
Kaundun, SS, Dale, RP, Zelaya, IA, Dinelli, G, Marotti, I, McIndoe, E, Cairns, A (2011) A novel P106L mutation in EPSPS and an unknown mechanism(s) act additively to confer resistance to glyphosate in a South African Lolium rigidum population. J Agric Food Chem 59, 32273233.
Lorentz, L, Gaines, TA, Nissen, SJ, Westra, P, Strek, HJ, Dehne, HW, Ruiz-Santaella, JP, Beffa, R (2014) Characterization of glyphosate resistance in Amaranthus tuberculatus populations. J Agric Food Chem 62, 81348142.
Malone, JM, Morran, S, Shirley, N, Boutsalis, P, Preston, C (2016) EPSPS gene amplification in glyphosate-resistant Bromus diandrus . Pest Manag Sci 72, 8188.
Mohseni-Moghadam, M, Schroeder, J, Ashigh, J (2013) Mechanism of resistance and inheritance in glyphosate resistant Palmer amaranth (Amaranthus palmeri) populations from New Mexico, USA. Weed Sci 61, 517525.
Monks, DW, Oliver, LR (1988) Interactions between soybean (Glycine max) cultivars and selected weeds. Weed Sci 36, 770774.
Moretti, ML, Van Horn, CR, Robertson, R, Segobye, K, Weller, SC, Young, BG, Johnson, WG, Douglas Sammons, R, Wang, D, Ge, X, d’Avignon, A (2017). Glyphosate resistance in Ambrosia trifida: Part 2. Rapid response physiology and non‐target‐site resistance. Pest Manag Sci, 10.1002/ps.4569
Nandula, VK, Ray, JD, Ribeiro, DN, Pan, Z, Reddy, KN (2013) Glyphosate resistance in tall waterhemp (Amaranthus tuberculatus) from Mississippi is due to both altered target-site and nontarget-site mechanisms. Weed Sci 61, 374383.
Nandula, VK, Wright, AA, Bond, JA, Ray, JD, Eubank, TW, Molin, WT (2014) EPSPS amplification in glyphosate-resistant spiny amaranth (Amaranthus spinosus): a case of gene transfer via interspecific hybridization from glyphosate-resistant Palmer amaranth (Amaranthus palmeri). Pest Manag Sci 70, 19021909.
Ng, C, Wickneswary, R, Salmijah, S, Teng, YT, Ismail, BS (2004) Glyphosate resistance in Eleusine indica (L.) Gaertn. from different origins and polymerase chain reaction amplification of specific alleles. Aust J Agric Res 55, 407414.
Perez, A, Alister, C, Kogan, M (2004) Absorption, translocation and allocation of glyphosate in resistant and susceptible Chilean biotypes of Lolium multiflorum . Weed Biol Manag 4, 5658.
Preston, C, Wakelin, AM (2008) Resistance to glyphosate from altered herbicide translocation patterns. Pest Manag Sci 64, 372376.
Ribeiro, DN, Pan, Z, Duke, SO, Nandula, VK, Baldwin, BS, Shaw, DR, Dayan, FE (2014) Involvement of facultative apomixis in inheritance of EPSPS gene amplification in glyphosate-resistant Amaranthus palmeri . Planta 239, 199212.
Rojano-Delgado, AM, Cruz-Hipolito, H, De Prado, R, de Castro, MD, Franco, AR (2012) Limited uptake, translocation and enhanced metabolic degradation contribute to glyphosate tolerance in Mucuna pruriens var. utilis plants. Phytochemistry 73, 3441.
Salas, RA, Burgos, NR, Tranel, PJ, Singh, S, Glasgow, L, Scott, RC, Nichols, RL (2016) Resistance to PPO-inhibiting herbicide in Palmer amaranth from Arkansas. Pest Manag Sci 72, 864869.
Salas, RA, Dayan, FE, Pan, Z, Watson, SB, Dickson, JW, Scott, RC, Burgos, NR (2012) EPSPS gene amplification in glyphosate-resistant Italian ryegrass (Lolium perenne ssp. multiflorum) from Arkansas. Pest Manag Sci 68, 12231230.
Salas-Perez, RA, Burgos, NR, Rangani, G, Singh, S, Refatti, JP, Piveta, L, Tranel, PJ, Mauromoustakos, A, Scott, RC (2017) Frequency of Gly-210 deletion mutation among protoporphyrinogen oxidase inhibitor–resistant Palmer amaranth (Amaranthus palmeri) populations. Weed Sci 65, 718731.
Shaner, DL, Lindenmeyer, RB, Ostlie, MH (2012) What have the mechanisms of resistance to glyphosate taught us? Pest Manag Sci 68, 39.
Van Horn, CR, Moretti, ML, Robertson, RR, Segobye, K, Weller, SC, Young, BG, Johnson, WG, Schulz, B, Green, AC, Jeffery, T, Lespérance, MA (2017). Glyphosate resistance in Ambrosia trifida: Part 1. Novel rapid cell death response to glyphosate. Pest Manag Sci, 10.1002/ps.4567
Varanasi, VK, Godar, AS, Currie, RS, Dille, AJ, Thompson, CR, Stahlman, PW, Jugulam, M (2015) Field-evolved resistance to four modes of action of herbicides in a single kochia (Kochia scoparia L. Schrad.) population. Pest Manag Sci 71, 12071212.
Vila-Aiub, MM, Balbi, MC, Distéfano, AJ, Fernández, L, Hopp, E, Yu, Q, Powles, SB (2012) Glyphosate resistance in perennial Sorghum halepense (johnsongrass), endowed by reduced glyphosate translocation and leaf uptake. Pest Manag Sci 68, 430436.
Wakelin, AM, Lorraine-Colwill, DF, Preston, C (2004) Glyphosate resistance in four different populations of Lolium rigidum as associated with reduced translocation of glyphosate to meristematic zones. Weed Res 44, 453459.
Ward, SM, Webster, TM, Steckel, LE (2013) Palmer amaranth (Amaranthus palmeri): a review. Weed Technol 27, 1227.
[WSSA] Weed Science Society of America (2016). WSSA Survey Ranks Palmer Amaranth as the Most Troublesome Weed in the U.S., Galium as the Most Troublesome in Canada. http://wssa. net/2016/04/wssa-survey-ranks-palmer-amaranth-as-the-mosttroublesome-weed-in-the-u-s-galium-as-the-most-troublesome-incanada. Accessed: June 2, 2017.
Wiersma, AT, Gaines, TA, Preston, C, Hamilton, JP, Giacomini, D, Buell, CR, Leach, JE, Westra, P (2015) Gene amplification of 5-enol-pyruvylshikimate-3-phosphate synthase in glyphosate-resistant Kochia scoparia . Planta 241, 463474.
Yu, Q, Cairns, A, Powles, S (2007) Glyphosate, paraquat and ACCase multiple herbicide resistance evolved in a Lolium rigidum biotype. Planta 225, 499513.
Yu, Q, Jalaludin, A, Han, H, Chen, M, Sammons, RD, Powles, SB (2015) Evolution of a double amino acid substitution in the 5-enolpyruvylshikimate-3-phosphate synthase in Eleusine indica conferring high-level glyphosate resistance. Plant Physiol 167, 14401447.


EPSPS Gene Amplification Primarily Confers Glyphosate Resistance among Arkansas Palmer amaranth (Amaranthus palmeri) Populations

  • Shilpa Singh (a1), Vijay Singh (a2), Amy Lawton-Rauh (a3), Muthukumar V. Bagavathiannan (a4) and Nilda Roma-Burgos (a5)...


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