Acetolactate Synthase–Inhibiting, Herbicide-Resistant Rice Flatsedge (Cyperus iria): Cross-Resistance and Molecular Mechanism of Resistance

Overuse of acetolactate synthase (ALS)–inhibiting herbicides in rice has led to the evolution of halosulfuron-resistant rice flatsedge in Arkansas and Mississippi. Resistant accessions were cross-resistant to labeled field rates of ALS-inhibiting herbicides from four different families, in comparison to a susceptible (SUS) biotype. Resistance index of Arkansas and Mississippi accessions based on an R/S ratio of the lethal dose required for 50% plant mortality (LD50) to bispyribac-sodium, halosulfuron, imazamox, and penoxsulam was ≥ 21-fold. Control of Arkansas, Mississippi, and SUS accessions with labeled field rates of 2,4-D, bentazon, and propanil was ≥ 93%. An enzyme assay revealed that an R/S ratio for 50% inhibition (I50) of ALS for halosulfuron was 2,600 and 200 in Arkansas and Mississippi, respectively. Malathion studies did not reveal enhanced herbicide metabolism in resistant plants. The ALS enzyme assay and cross-resistance studies point toward altered a target site as the potential mechanism of resistance. Trp574–Leu amino acid substitution within the ALS gene was found in both Arkansas and Mississippi rice flatsedge accessions using the Illumina HiSeq platform, which corresponds to the mechanism of resistance found in many weed species. Field-rate applications of 2,4-D, bentazon, and propanil can be used to control these ALS-resistant rice flatsedge accessions.

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ALS-Resistant Smallflower Umbrella Sedge (Cyperus difformis) in Arkansas Rice: Physiological and Molecular Basis of Resistance

Weed Science ◽

10.1614/ws-d-14-00147.1 ◽

2015 ◽

Vol 63 (3) ◽

pp. 561-568 ◽

Cited By ~ 12

Author(s):

Parsa Tehranchian ◽

Dilpreet S. Riar ◽

Jason K. Norsworthy ◽

Vijay Nandula ◽

Scott McElroy ◽

...

Keyword(s):

Massively Parallel Sequencing ◽

Lethal Dose ◽

Acetolactate Synthase ◽

Control Measures ◽

Effective Control ◽

Weed Species ◽

Illumina Hiseq ◽

Mechanism Of Resistance ◽

Cyperus Difformis

Smallflower umbrella sedge is a problematic weed in direct-seeded rice in the midsouthern United States. It recently has evolved resistance to the acetolactate synthase (ALS) –inhibiting herbicide halosulfuron in Arkansas rice. Studies were conducted (1) to determine if the resistant biotype is cross resistant to other ALS-inhibiting herbicides, (2) to evaluate alternative herbicide control options, and (3) to determine the mechanism of resistance. Whole-plant bioassay revealed that halosulfuron-resistant plants were not controlled by bispyribac–sodium, imazamox, and penoxsulam at the labeled field rate of each herbicide. The level of resistance to these herbicides, based on the lethal dose needed to kill 50% of plants (LD50) was ≥ 15-fold compared to a susceptible biotype. Both biotypes were controlled >96% with bentazon and propanil and ≤ 23% with quinclorac, thiobencarb, and 2,4-D. Hence, effective control measures exist; albeit, the number of herbicide options appear limited. Based on in vitro ALS enzyme assays, altered target site is the mechanism of resistance to halosulfuron and imazamox. Massively parallel sequencing with the use of the Illumina HiSeq detected an amino acid substitution of Pro197-to-His in the resistant biotype that is consistent with ALS-inhibiting herbicide resistance in other weed species.

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Herbicide resistance in China: a quantitative review

Weed Science ◽

10.1017/wsc.2019.46 ◽

2019 ◽

Vol 67 (6) ◽

pp. 605-612 ◽

Cited By ~ 2

Author(s):

Xiangying Liu ◽

Shihai Xiang ◽

Tao Zong ◽

Guolan Ma ◽

Lamei Wu ◽

...

Keyword(s):

Herbicide Resistance ◽

Crop Production ◽

Rapid Evolution ◽

Acetolactate Synthase ◽

Cross Resistance ◽

Weed Species ◽

Herbicide Resistant ◽

Auxin Herbicides ◽

Economic Boom ◽

Meta Analyses

AbstractThe widespread, rapid evolution of herbicide-resistant weeds is a serious and escalating agronomic problem worldwide. During China’s economic boom, the country became one of the most important herbicide producers and consumers in the world, and herbicide resistance has dramatically increased in the past decade and has become a serious threat to agriculture. Here, following an evidence-based PRISMA (preferred reporting items for systematic reviews and meta-analyses) approach, we carried out a systematic review to quantitatively assess herbicide resistance in China. Multiple weed species, including 26, 18, 11, 9, 5, 5, 4, and 3 species in rice (Oryza sativa L.), wheat (Triticum aestivum L.), soybean [Glycine max (L.) Merr.], corn (Zea mays L.), canola (Brassica napus L.), cotton (Gossypium hirsutum L.)., orchards, and peanut (Arachis hypogaea L.) fields, respectively, have developed herbicide resistance. Acetolactate synthase inhibitors, acetyl-CoA carboxylase inhibitors, and synthetic auxin herbicides are the most resistance-prone herbicides and are the most frequently used mechanisms of action, followed by 5-enolpyruvylshikimate-3-phosphate synthase inhibitors and protoporphyrinogen oxidase inhibitors. The lack of alternative herbicides to manage weeds that exhibit cross-resistance or multiple resistance (or both) is an emerging issue and poses one of the greatest threats challenging the crop production and food safety both in China and globally.

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Resistance to acetolactate synthase inhibitors and quinclorac in a biotype of false cleavers (Galium spurium)

Weed Science ◽

10.1017/s0043174500090780 ◽

1998 ◽

Vol 46 (4) ◽

pp. 390-396 ◽

Cited By ~ 46

Author(s):

Linda M. Hall ◽

Kim M. Stromme ◽

Geoff P. Horsman ◽

Malcolm D. Devine

Keyword(s):

Herbicide Resistance ◽

Acetolactate Synthase ◽

Field Analysis ◽

Cross Resistance ◽

Weed Species ◽

Mechanism Of Resistance ◽

Als Inhibitors ◽

High Level ◽

Galium Spurium ◽

Moderately Resistant

A false cleavers population that survived treatment with triasulfuron/bromoxynil in 1996 was identified in central Alberta, Canada, in a field that had been treated with acetolactate synthase (ALS) inhibitors in 3 of the previous 6 yr. In greenhouse studies, this biotype was highly resistant to the ALS inhibitors triasulfuron, thifensulfuron/tribenuron, and sulfometuron and moderately resistant to imazethapyr; GR50, values were > 16, > 5, > 1.0, and 9.9, respectively. In addition, cross-resistance was identified to the auxin-type herbicide quinclorac (GR50 value > 6.7) but not to fluroxypyr (GR50 value 1) or MCPA/mecoprop/dicamba. Quinclorac had not been used previously in this field. Analysis of ALS extracted from the resistant biotype and a susceptible biotype from a nearby location indicated that resistance to ALS inhibitors was due to an altered target site with reduced sensitivity to a broad range of ALS inhibitors. The ALS I50 values for triasulfuron, metsulfuron, chlorsulfuron, thifensulfuron, and imazethapyr were 36, 34, 92, 96, and 14 times higher, respectively, for the resistant compared to the susceptible biotype. The mechanism of resistance to quinclorac is unknown. This is the first report of high-level herbicide resistance in this weed species.

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Evaluation of Herbicide-Resistance Status on Populations of Littleseed Canarygrass (Phalaris Minor Retz.) from Southern Greece and Suggestions for their Effective Control

Journal of Plant Protection Research ◽

10.2478/v10045-012-0050-3 ◽

2012 ◽

Vol 52 (3) ◽

pp. 308-313 ◽

Cited By ~ 7

Author(s):

Ilias Travlos

Keyword(s):

Herbicide Resistance ◽

Resistance Index ◽

Acetolactate Synthase ◽

Effective Control ◽

Cross Resistance ◽

Resistance Mutations ◽

Resistance Level ◽

Phalaris Minor ◽

Wide Range ◽

Southern Greece

Evaluation of Herbicide-Resistance Status on Populations of Littleseed Canarygrass (Phalaris MinorRetz.) from Southern Greece and Suggestions for their Effective ControlIn 2010, a survey was conducted in the wheat fields of a typical cereal-producing region of Greece to establish the frequency and distribution of herbicide-resistant littleseed canarygrass (Phalaris minorRetz.). In total, 73 canarygrass accessions were collected and screened in a field experiment with several herbicides commonly used to control this weed. Most of the weed populations were classed as resistant (or developing resistance) to the acetyl-CoA varboxylase (ACCase)-inhibiting herbicide diclofop, while resistance to clodinafop was markedly lower. The results of the pot experiments showed that some of the canary populations were found to have a very high level of diclofop resistance (resistance index up to 12.4), while cross resistance with other herbicides was also common. The levels of resistance and cross resistance patterns among populations varied along with the different amounts and times of selection pressure. Such variation indicated either more than one mechanism of resistance or different resistance mutations in these weed populations. The population which had the highest diclofop resistance level, showed resistance to all aryloxyphenoxypropinate (APP) herbicides applied and non-ACCase inhibitors. Alternative ACCase-inhibiting herbicides, such as pinoxaden remain effective on the majority of the tested canarygrass populations, while the acetolactate synthase (ALS)-inhibiting herbicide mesosulfuron + iodosulfuron could also provide some solutions. Consequently, there is an opportunity to effectively control canarygrass by selecting from a wide range of herbicides. It is the integration of agronomic practices with herbicide application, which helps in effective management ofP. minorand particularly its resistant populations.

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Wild oat (Avena fatua L.) biotypes resistant to acetolactate synthase and acetyl-CoA carboxylase inhibitors in Poland

Plant Soil and Environment ◽

10.17221/177/2013-pse ◽

2013 ◽

Vol 59 (No. 9) ◽

pp. 432-437 ◽

Cited By ~ 7

Author(s):

K. Adamczewski ◽

R. Kierzek ◽

K. Matysiak

Keyword(s):

Resistance Index ◽

Acetolactate Synthase ◽

Avena Fatua ◽

Multiple Resistance ◽

Wild Oat ◽

Acetyl Coa Carboxylase ◽

Site Mutation ◽

Metabolic Resistance ◽

Mechanism Of Resistance ◽

And Control

The aim of the study was to collect seeds of wild oat from the fields where, in spite of the applied herbicides, the weed is very poorly controlled, and to determine under greenhouse conditions if any resistant biotypes are present. In the years 2008–2011, 34 samples of wild oat were collected from fields where the weed was poorly controlled. The biotypes were analyzed in greenhouse experiments to determine if they are resistant to herbicides. Among five resistant biotypes three of them (R3, R4 and R5) were resistant only to iodosulfuron and mesosulfuron, and biotype R2 – only to propoxycarbazone-sodium. Biotype R1 exhibited multiple resistance to iodosulfuron + mesosulfuron and pinoxaden. The use of sulfometuron proves that the mechanism of resistance of two biotypes of wild oat (R1 and R4) to acetolactate synthase inhibitors is associated with target-site mutation. The curve of biotypes R3 and R5 controlled with iodosulfuron + mesosulfuron shows a relatively low resistance index and control of those biotypes with sulfometuron indicates a metabolic resistance.

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Environmental Impact of Glyphosate-Resistant Weeds in Canada

Weed Science ◽

10.1614/ws-d-13-00093.1 ◽

2014 ◽

Vol 62 (2) ◽

pp. 385-392 ◽

Cited By ~ 18

Author(s):

Hugh J. Beckie ◽

Peter H. Sikkema ◽

Nader Soltani ◽

Robert E. Blackshaw ◽

Eric N. Johnson

Keyword(s):

Environmental Impact ◽

Weed Control ◽

Acetolactate Synthase ◽

Application Rate ◽

Weed Species ◽

Common Ragweed ◽

Herbicide Resistant ◽

Herbicide Treatments ◽

Relative Potential ◽

Synthase Inhibitor

Glyphosate-resistant (GR) giant ragweed, horseweed, and common ragweed were confirmed in southwestern Ontario, Canada in 2008, 2010, and 2011, respectively. In the western prairie provinces of Alberta and Saskatchewan, GR (plus acetolactate synthase inhibitor-resistant) kochia was discovered in 2011. This symposium paper estimates the environmental impact (EI) of the top herbicide treatments or programs used to manage these GR weed species in the major field crops grown in each region. For each herbicide treatment, EI (per ha basis) was calculated as the environmental impact quotient (EIQ), which quantifies the relative potential risk of pesticide active ingredients on human and ecological health based on risk components to farm workers, consumers, and the environment, multiplied by the application rate (kg ai ha−1). Total EI is defined as EI (per ha basis) multiplied by the application area (i.e., land area affected by a GR weed). It was assumed that all herbicide treatments would supplement the continued usage of glyphosate because of its broad spectrum weed control. For the control of these GR weeds, most treatments contain auxinic or protoporphyrinogen oxidase (PPO)-inhibiting herbicides. The majority of auxinic herbicide treatments result in low (EI ≤ 10) to moderate (11 to 20) EI, whereas all treatments of PPO inhibitors have low EI. Total EI of GR horseweed and kochia will generally be greater than that of giant or common ragweed because of rapid seed dispersal. For recommended herbicide treatments to control GR weeds (and herbicide-resistant weeds in general), EI data should be routinely included with cost and site of action in weed control extension publications and software, so that growers have the information needed to assess the EI of their actions.

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Widespread Occurrence of Herbicide-Resistant Italian Ryegrass (Lolium multiflorum) in Northern Idaho and Eastern Washington

Weed Technology ◽

10.1614/wt-d-09-00059.1 ◽

2010 ◽

Vol 24 (3) ◽

pp. 281-288 ◽

Cited By ~ 27

Author(s):

Traci A. Rauch ◽

Donald C. Thill ◽

Seth A. Gersdorf ◽

William J. Price

Keyword(s):

Pacific Northwest ◽

Cropping Systems ◽

Lolium Multiflorum ◽

Acetolactate Synthase ◽

Italian Ryegrass ◽

Cross Resistance ◽

Herbicide Resistant ◽

Group 2 ◽

Northern Idaho ◽

Eastern Washington

Persistent use of herbicides has resulted in the selection of many herbicide-resistant weeds worldwide. A survey of 75 fields in the Palouse region of the inland Pacific Northwest was conducted to determine the extent of Italian ryegrass resistance to grass herbicides commonly used in winter wheat-cropping systems. Plants grown from collected seed samples were tested for resistance to diclofop, clodinafop, quizalofop, tralkoxydim, sethoxydim, clethodim, pinoxaden, triasulfuron, mesosulfuron, flucarbazone, imazamox, and flufenacet/metribuzin. Averaged across herbicide families within a herbicide group, some level of resistance was exhibited in 73, 31, and 31% of the populations to the aryloxyphenoxypropionates, cyclohexanediones, and phenylpyrazoline herbicides, respectively, and 39, 53, and 55% of the populations to the sulfonylureas, sulfonylaminocarbonyltriazolinone, and imidazolinone herbicides, respectively. Twelve percent of the populations showed some level of resistance to flufenacet/metribuzin. Cross-resistance to all acetyl coenzyme A carboxylase-inhibiting (group 1) herbicides was observed in 12% of the populations, whereas 25% of the populations were cross-resistant to all acetolactate synthase-inhibiting (group 2) herbicides tested. Of all the populations tested, 7% exhibited multiple resistance to at least one herbicide within all three groups tested. Only 5% of populations were completely susceptible to all 12 herbicides tested. These results indicate that herbicide-resistant Italian ryegrass populations are now common across much of the Palouse region in northern Idaho and eastern Washington.

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Acetolactate Synthase (ALS) Target-Site Mutations in ALS Inhibitor-Resistant Russian Thistle (Salsola tragus)

Weed Science ◽

10.1614/ws-d-09-00083.1 ◽

2010 ◽

Vol 58 (3) ◽

pp. 244-251 ◽

Cited By ~ 26

Author(s):

Suzanne I. Warwick ◽

Connie A. Sauder ◽

Hugh J. Beckie

Keyword(s):

Molecular Basis ◽

Genome Structure ◽

Acetolactate Synthase ◽

Molecular Techniques ◽

Target Site ◽

Weed Species ◽

Single Nucleotide ◽

Herbicide Resistant ◽

Inhibitor Resistance ◽

Als Inhibitor

ALS inhibitor-resistant biotypes are the fastest growing class of herbicide-resistant (HR) weeds. A Canadian ALS inhibitor-resistant biotype of Russian thistle was first reported in 1989. The molecular basis for ALS-inhibitor resistance is unknown for Canadian populations of this polyploid weed species, and was determined in this study for one Alberta and two Saskatchewan HR Russian thistle populations. HR plants survived spray application of the ALS-inhibitor mixture thifensulfuron : tribenuron in the greenhouse. All three HR Russian thistle populations were heterogeneous and contained both HR and herbicide-susceptible (HS) individuals. The molecular basis for resistance was determined by sequencing theALSgene and/or conducting a TaqMan genotyping assay for single nucleotide polymorphism (SNP) for the Trp574Leu mutation. Two target-site mutations were observed: Trp574Leu in all three biotypes (554 individuals) and Pro197Gln in one biotype (one individual), suggesting multiple-founding events for Russian thistle HR populations in western Canada. Segregation patterns among F1 and F2 progeny arrays of HR lines sprayed under greenhouse conditions varied; some segregated (i.e., had HR and HS progeny), whereas other lines were exclusively HR. In contrast, no segregation of molecular types, i.e., Trp574, Trp/Leu574and Leu574, as would be expected with heterozygosity at a single locus Trp/Leu574, was observed. Such lack of segregation is consistent with the polyploid genome structure of Russian thistle and the presence of two copies of theALSgene. The presence of more than oneALSgene confounded the ability of the molecular techniques to accurately identify “true” heterozygotes in this study.

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Frequency, distribution, and ploidy diversity of herbicide-resistant Italian ryegrass (Lolium perenne spp. multiflorum) populations of western Oregon

Weed Science ◽

10.1017/wsc.2021.2 ◽

2021 ◽

pp. 1-33

Author(s):

Lucas K. Bobadilla ◽

Andrew G. Hulting ◽

Pete A Berry ◽

Marcelo L. Moretti ◽

Carol Mallory-Smith

Keyword(s):

Lolium Perenne ◽

Herbicide Resistance ◽

Plant Density ◽

Acetolactate Synthase ◽

Italian Ryegrass ◽

Cross Resistance ◽

Ploidy Levels ◽

Herbicide Resistant ◽

Feral Populations ◽

First Time

Abstract Italian ryegrass [Lolium perenne L. spp. multiflorum (Lam.) Husnot] is one of the most troublesome weeds worldwide. L. multiflorum is also a grass seed crop cultivated on 50,000 ha in Oregon, where both diploid and tetraploid cultivars are grown. A survey was conducted to understand the distribution, frequency, and susceptibility of L. multiflorum to selected herbicides used to control L. multiflorum. The herbicides selected were clethodim, glufosinate, glyphosate, mesosulfuron-methyl (mesosulfuron), paraquat, pinoxaden, pyroxsulam, quizalofop-P-ethyl (quizolafop), pronamide, flufenacet + metribuzin, and pyroxasulfone. The ploidy levels of the populations were also tested. A total of 150 fields were surveyed between 2017 and 2018, of which 75 (50%) had L. multiflorum present. Herbicide-resistant populations were documented in 88% of the 75 populations collected. The most frequent mechanisms of action were resistance to Acetyl-CoA carboxylase (ACCase), Acetolactate Synthase (ALS), 5-enolpyruvylshikimate-3-phosphate (EPSPs) inhibitors, and combinations thereof. Multiple and cross-resistance, found in 75% of the populations, were the most frequent patterns of resistance. Paraquat-resistant biotypes were confirmed in six orchard crop populations for the first time in Oregon. Herbicide resistance was spatially clustered, with most cases of resistance in the northern part of the surveyed area. ALS and ACCase resistant populations were prevalent in wheat (Triticum aestivum L.) fields. Multiple-resistance was positively correlated with plant density. Tetraploid feral populations were identified, but no cases of herbicide resistance were documented. This is the first survey of herbicide resistance and ploidy diversity in L. multiflorum in western Oregon. Resistant populations were present across the surveyed area, indicating that the problem is widespread.

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Confirmation of Shattercane (Sorghum bicolor) Resistance to ALS-Inhibiting Herbicides in Ohio

Plant Health Progress ◽

10.1094/php-2002-1021-01-rs ◽

2002 ◽

Vol 3 (1) ◽

pp. 2

Author(s):

Traci L. Brenly-Bultemeier ◽

Jeff Stachler ◽

S. Kent Harrison

Keyword(s):

Sorghum Bicolor ◽

Soil Seed Bank ◽

Resistance Mechanism ◽

Acetolactate Synthase ◽

Dry Weight ◽

Cross Resistance ◽

Herbicide Resistant ◽

Shoot Dry Weight ◽

Als Inhibitors ◽

Sorghum Bicolor L

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.

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