The Evidence for Reduced Glyphosate Efficacy on Acetolactate Synthase–Inhibiting Herbicide-Resistant Yellow Nutsedge (Cyperus esculentus)

Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 389-398
Author(s):  
Parsa Tehranchian ◽  
Jason K. Norsworthy ◽  
Matheus Palhano ◽  
Nicholas E. Korres ◽  
Scott McElroy ◽  
...  

A yellow nutsedge biotype (Res) from an Arkansas rice field has evolved resistance to acetolactate synthase (ALS)-inhibiting herbicides. TheResbiotype previously exhibited cross-resistance to ALS inhibitors from four chemical families (imidazolinone, pyrimidinyl benzoate, sulfonylurea, and triazolopyrimidine). Experiments were conducted to evaluate alternative herbicides (i.e., glyphosate, bentazon, propanil, quinclorac, and 2,4-D) currently labeled in Arkansas rice–soybean production systems. Based on the percentage of aboveground dry weight reduction, control of the yellow nutsedge biotypes with the labeled rate of bentazon, propanil, quinclorac, and 2,4-D was < 44%. Glyphosate (867 g ae ha−1) resulted in 68 and > 94% control of theResand susceptible yellow nutsedge biotypes, respectively, at 28 d after treatment. Dose-response studies were conducted to estimate the efficacy of glyphosate on theResbiotype, three susceptible yellow nutsedge biotypes, and purple nutsedge. Based on the dry weights, theResbiotype was ≥ 5- and ≥ 1.3-fold less responsive to glyphosate compared to the susceptible biotypes and purple nutsedge, respectively. Differences in absorption and translocation of radiolabeled glyphosate were observed among the yellow nutsedge biotypes and purple nutsedge. The susceptible biotype had less14C-glyphosate radioactivity in the tissues above the treated leaf and greater radioactivity in tissues below the treated leaf compared to theResbiotype and purple nutsedge. Reduced translocation of glyphosate in tissues below the treated leaf of theResbiotype could be a reason for the lower glyphosate efficacy in theResbiotype. No amino acid substitution that would correspond to glyphosate resistance was found in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene of theResbiotype. However, an amino acid (serine) addition was detected in the EPSPS gene of theResbiotype; albeit, it is not believed that this addition contributes to lower efficacy of glyphosate in this biotype.

Weed Science ◽  
2019 ◽  
Vol 67 (3) ◽  
pp. 281-287 ◽  
Author(s):  
Jiapeng Fang ◽  
Tingting Liu ◽  
Yuhua Zhang ◽  
Jun Li ◽  
Liyao Dong

AbstractBarnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] is acknowledged to be the most troublesome weed in rice fields in Anhui and Jiangsu provinces of China. It cannot be effectively controlled using certain acetolactate synthase (ALS)-inhibiting herbicides, including penoxsulam. Echinochloa crus-galli samples with suspected resistance to penoxsulam were collected to identify the target site–based mechanism underlying this resistance. Populations AXXZ-2 and JNRG-2 showed 33- and 7.3-fold resistance to penoxsulam, respectively, compared with the susceptible JLGY-3 population. Cross-resistance to other ALS inhibitors was reported in AXXZ-2 but not in JNRG-2, and occasionally showed higher sensitivity than JLGY-3. In vitro ALS activity assays revealed that penoxsulam concentrations required to inhibit 50% of ALS activity were 11 and 5.2 times greater in AXXZ-2 and JNRG-2, respectively, than in JLGY-3. DNA and predicted amino acid sequence analyses of ALS revealed Ala-205-Val and Ala-122-Gly substitutions in AXXZ-2 and JNRG-2, respectively. Our results indicate that these substitutions in ALS are at least partially responsible for resistance to penoxsulam.


2002 ◽  
Vol 3 (1) ◽  
pp. 2
Author(s):  
Traci L. Brenly-Bultemeier ◽  
Jeff Stachler ◽  
S. Kent Harrison

A population of shattercane (Sorghum bicolor (L.) Moench) located in Fairfield County, Ohio, was investigated for herbicide resistance after it persisted in a field that had been treated repeatedly with herbicides that inhibit acetolactate synthase (ALS). Herbicide bioassays confirmed cross-resistance of the suspected resistant (R) population to the ALS inhibitors nicosulfuron, primisulfuron, and imazethapyr. Herbicide doses required to reduce R shattercane shoot dry weight 50% (i.e., the GR50 values) were > 35,000, > 40,000, and 34,215 g ai/ha for nicosulfuron, primisulfuron, and imazethapyr, respectively. In contrast, GR50 values for the same herbicides applied to a susceptible (S) shattercane population from an adjacent county were 0.185, 0.025, and 0.038 g/ha, respectively. The high levels of resistance exhibited by the R population suggest that the resistance mechanism is due to one or more alterations in ALS, the herbicide target site. Effective management of ALS herbicide-resistant shattercane will require an integrated strategy designed to isolate the R population and deplete its soil seed bank while minimizing herbicide selection pressure. Accepted for publication 14 October 2002. Published 21 October 2002.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Maria J. García ◽  
Candelario Palma-Bautista ◽  
José G. Vazquez-Garcia ◽  
Antonia M. Rojano-Delgado ◽  
María D. Osuna ◽  
...  

Abstract Amaranthus hybridus is one of the main weed species in Córdoba, Argentina. Until recently, this weed was effectively controlled with recurrent use of glyphosate. However, a population exhibiting multiple resistance (MR2) to glyphosate and imazamox appeared in a glyphosate resistant (GR) soybean field, with levels of resistance up to 93 and 38-fold higher to glyphosate and imazamox, respectively compared to the susceptible (S) population. In addition to imidazolinones, MR2 plants showed high resistance levels to sulfonylamino-carbonyl (thio) benzoates and moderate resistance to sulfonylureas and triazolopyrimidines. Multiple amino acid substitutions were found in both target genes, acetolactate synthase (ALS) and 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), responsible for conferring high herbicides resistance levels in this A. hybridus population. In the case of EPSPS, the triple amino acid substitution TAP-IVS was found. In addition, MR2 plants also showed increased EPSPS gene expression compared to susceptible plants. A Ser653Asn substitution was found in the ALS sequence of MR2, explaining the pattern of cross-resistance to the ALS-inhibitor herbicide families found at the ALS enzyme activity level. No other mutations were found in other conserved domains of the ALS gene. This is the first report worldwide of the target site resistance mechanisms to glyphosate and ALS inhibitors in multiple herbicide resistance Amaranthus hybridus.


Weed Science ◽  
2018 ◽  
Vol 66 (4) ◽  
pp. 424-432 ◽  
Author(s):  
Javid Gherekhloo ◽  
Zahra M. Hatami ◽  
Ricardo Alcántara-de la Cruz ◽  
Hamid R. Sadeghipour ◽  
Rafael De Prado

AbstractWild mustard (Sinapis arvensis L.) is a weed that frequently infests winter wheat (Triticum aestivum L.) fields in Golestan province, Iran. Tribenuron-methyl (TM) has been used recurrently to control this species, thus selecting for resistant S. arvensis populations. The objectives were: (1) to determine the resistance level to TM of 14 putatively resistant (PR) S. arvensis populations, collected from winter wheat fields in Golestan province, Iran, in comparison to one susceptible (S) population; and (2) to characterize the resistance mechanisms and the potential evolution of cross-resistance to other classes of acetolactate synthase (ALS)-inhibiting herbicides in three populations (AL-3, G-5, and Ag-Sr) confirmed as being resistant (R) to TM. The TM doses required to reduce the dry weight of the PR populations by 50% were between 2.2 and 16.8 times higher than those needed for S plants. The ALS enzyme activity assays revealed that the AL-3, G-5, and Ag-Sr populations evolved cross-resistance to the candidate ALS-inhibiting herbicides from the sulfonylureas (SU), triazolopyrimidines (TP), pyrimidinyl-thiobenzoates (PTB), sulfonyl-aminocarbonyl-triazolinone (SCT), and imidazolinones (IMI) classes. No differences in absorption, translocation, or metabolism of [14C]TM between R and S plants were observed, suggesting that these non-target mechanisms were not responsible for the resistance. The ALS gene of the R populations contained the Trp-574-Leu mutation, conferring cross-resistance to the SU, SCT, PTB, TP, and IMI classes. The Trp-574-Leu mutation in the ALS gene conferred cross-resistance to ALS-inhibiting herbicides in S. arvensis from winter wheat fields in Golestan province. This is the first TM resistance case confirmed in this species in Iran.


Weed Science ◽  
1998 ◽  
Vol 46 (1) ◽  
pp. 24-29 ◽  
Author(s):  
Terry R. Wright ◽  
Donald Penner

Acetolactate synthase (ALS)-inhibiting herbicide carryover in soil can severely affect sugarbeets grown in the year(s) following application. Two newly developed imidazolinone-resistant (IMI-R) sugarbeet somatic cell selections (Sir-13 and 93R30B) were examined for magnitude of resistance and extent of cross-resistance to other classes of ALS inhibitors and compared to a previously developed sulfonylurea-resistant (SU-R) selection, Sur. In vitro shoot culture tests indicated Sir-13 resistance was specific to imidazolinone (IMI) herbicides at approximately a 100-fold resistance compared to the sensitive control sugarbeet. Sur was 10,000-fold resistant to the sulfonylurea (SU) herbicide, chlorsulfuron, and 40-fold resistant to the triazolopyrimidine sulfonanilide (TP) herbicide, flumetsulam, but not cross-resistant to the IMI herbicides. 93R30B was selected for IMI-R from a plant homozygous for the SU-R allele,Sur, and displayed similar in vitro SU-R and TP-R as Sur, but also displayed a very high resistance to various IMI herbicides (400- to 3,600-fold). Compared to the sensitive control, Sir-13 was 300- and > 250-fold more resistant to imazethapyr and imazamox residues in soil, respectively. Response by whole plants to postemergence herbicide applications was similar to that observed in shoot cultures. Sir-13 exhibited > 100-fold resistance to imazethapyr as well as imazamox, and 93R30B showed > 250-fold resistance to both herbicides. 93R30B showed great enough resistance to imazamox to merit consideration of imazamox for use as a herbicide in these sugarbeets. Sir-13 showed a two- to threefold higher level of resistance in the homozygous vs. heterozygous state, indicating that like most ALS-inhibitor resistance traits, it was semidominantly inherited.


Weed Science ◽  
1997 ◽  
Vol 45 (2) ◽  
pp. 229-233 ◽  
Author(s):  
Bielinski M. Santos ◽  
Thomas A. Bewick ◽  
William M. Stall ◽  
Donn G. Shilling

Replacement series experiments were conducted under greenhouse conditions to evaluate effects of population densities and proportions on the intraspecific and interspecific interference of either purple nutsedge or yellow nutsedge with tomato cv. Sunny, under nonlimiting conditions of water and nutrients. When grown with either nutsedge species for 40 d, tomato dry weight per plant increased and dry weight per plant of nutsedge decreased as their relative proportions decreased in mixture. Relative yield analysis indicated tomato is a stronger competitor than either nutsedge species. Both nutsedges appeared to be weak interspecific competitors but strong intraspecific competitors. Attenuated light on a purple nutsedge canopy showed that tomato additions can reduce light received by the weed compared to pure nutsedge stands.


2008 ◽  
Vol 22 (4) ◽  
pp. 602-608 ◽  
Author(s):  
Rodrigo Figueroa ◽  
Marlene Gebauer ◽  
Albert Fischer ◽  
Marcelo Kogan

Bensulfuron-methyl (BSM) has been one of the most widely used herbicides in Chilean rice fields because it controls a wide spectrum of weeds and does not require field drainage for application. However, failures of BSM to control water plantain in rice fields have been noted since 2002. We assessed BSM effects on suspected resistant (CU1 and CU2) and susceptible (AN1) water plantain accessions collected in Chilean rice fields during 2004 and 2005. BSM rates resulting in 50% growth reduction (GR50) of CU2 and CU1 plants were 12- and 33-fold higher than for AN1 plants, respectively. Acetolactate synthase (ALS) activity assays in vitro suggested resistance in CU1 and CU2 was due to an ALS enzyme with reduced BSM sensitivity compared to the AN1 biotype. Resistance indices (RI), or ratios of the resistant to susceptibleI50values (BSM rate to inhibit ALS-enzyme activity by 50%), were 266 (CU2/AN1) and > 38,462 (CU1/AN1). This agreed with in vivo ALS activity assays whereRIwere 224 (CU2/AN1) and > 8,533 (CU1/AN1). Resistance levels detected in whole-plant or in vivo ALS activity assays were orders of magnitude lower than those detected in in vitro ALS activity studies suggesting nontarget site mechanisms may have mitigated BSM toxicity. However, a consistent ranking of BSM sensitivity levels (AN1 > CU2 > CU1) throughout all three types of assays suggests resistance is primarily endowed by low target site sensitivity. We conclude that susceptible and resistant water plantain biotypes coexist in Chilean paddies, and the use of integrated weed management involving herbicides with a different mode of action would be imperative to prevent further evolution of resistance to BSM and possibly cross-resistance to other ALS inhibitors. In vitro ALS-enzyme assays provided the best discrimination of resistance levels between biotypes.


Weed Science ◽  
2011 ◽  
Vol 59 (3) ◽  
pp. 431-437 ◽  
Author(s):  
Suphannika Intanon ◽  
Alejandro Perez-Jones ◽  
Andrew G. Hulting ◽  
Carol A. Mallory-Smith

Mayweed chamomile seeds were collected from six different fields across the Pacific Northwest. All populations (each collection site was considered a population) were suspected to have some level of acetolactate synthase (ALS) resistance. Greenhouse and laboratory studies were conducted to determine if these populations were resistant to three different classes of ALS inhibitors: sulfonylureas (SU), imidazolinones (IMI), and triazolopyrimidines (TP). A whole-plant dose–response andin vitroALS activity studies confirmed cross-resistance to thifensulfuron + tribenuron/chlorsulfuron (SU), imazethapyr (IMI), and cloransulam (TP); however, resistance varied by herbicide class and population. TwoALSisoforms of theALSgene (ALS1andALS2) were identified in mayweed chamomile; however, only mutations inALS1were responsible for resistance. No mutations were found inALS2. Sequence analysis of the partialALSgene identified four point mutations at position 197 (Pro197to Leu, Gln, Thr, or Ser) in the resistant populations. This study demonstrates genotypic variation associated with cross-resistance to ALS inhibitors within and between populations.


1993 ◽  
Vol 7 (4) ◽  
pp. 900-905 ◽  
Author(s):  
John S. Richburg ◽  
John W. Wilcut ◽  
Glenn R. Wehtje

Greenhouse studies were conducted to determine the response of purple and yellow nutsedges to selective soil placement of 5 cm of soil treated with imazethapyr above and/or below the nutsedge tubers. Early postemergence (EPOST) or postemergence (POST) imazethapyr treatments at 71 g ai/ha as a foliar, soil, or foliar + soil application was also evaluated. Imazethapyr placement above or below the nutsedge tuber generally increased shoot number, shoot dry weight (SW), shoot regrowth dry weight (SRW), and root tuber dry weight (RTW) production in both species, 28 and 42 days after treatment (DAT) compared with the control. However, the 5-cm above + 5-cm below tuber treatment at 14, 28, and 42 DAT reduced purple nutsedge shoot number, SW, SRW, and RTW to 19, 7, 14, and 26% of the control, respectively. Yellow nutsedge shoot number was 103% of the control with the 5-cm above + 5-cm below tuber treatment 42 DAT. The 5-cm above + 5-cm below tuber treatment reduced yellow nutsedge SW, SRW, and RTW to 43, 44, and 23% of the control, respectively, 28 and 42 DAT. EPOST and POST foliar + soil and soil-only applications reduced SW 28 d after treatment (DAT) to 13% or less of the control for both species. SRWs of both species were ≤ 53% of the control 42 DAT for the soil-only application. The foliar-only treatment was the least effective in SW, SRW, and RTW reductions.


1995 ◽  
Vol 9 (2) ◽  
pp. 277-280 ◽  
Author(s):  
J. K. Peterson ◽  
H. F. Harrison

The allelopathic influence of sweet potato cultivar ‘Regal’ on purple nutsedge was compared to the influence on yellow nutsedge under controlled conditions. Purple nutsedge shoot dry weight, total shoot length and tuber numbers were significantly lower than the controls (47, 36, and 19% inhibition, respectively). The influence on the same parameters for yellow nutsedge (35, 21, and 43% inhibition, respectively) were not significantly different from purple nutsedge. Sweet potato shoot dry weight was inhibited by purple and yellow nutsedge by 42% and 45%, respectively. The major allelopathic substance from ‘Regal’ root periderm tissue was isolated and tested in vitro on the two sedges. The I50's for shoot growth, root number, and root length were 118, 62, and 44 μg/ml, respectively, for yellow nutsedge. The I50's for root number and root length were 91 and 85 μg/ml, respectively, for purple nutsedge and the I50for shoot growth could not be calculated.


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