Controlling Herbicide-Resistant Annual Bluegrass (Poa annua) Phenotypes with Methiozolin

2017 ◽  
Vol 31 (3) ◽  
pp. 470-476 ◽  
Author(s):  
James T. Brosnan ◽  
Jose J. Vargas ◽  
Gregory K. Breeden ◽  
Sarah L. Boggess ◽  
Margaret A. Staton ◽  
...  
Keyword(s):  
Acetolactate Synthase ◽  
Target Site ◽  
Multiple Resistance ◽  
Herbicide Resistant ◽  
Annual Bluegrass ◽  
Microtubule Inhibitors ◽  
Effective Option ◽  
Target Site Resistance ◽  
Susceptible Control ◽  
Als Inhibitors

Methiozolin is an isoxazoline herbicide being investigated for selective POST annual bluegrass control in managed turfgrass. Research was conducted to evaluate methiozolin efficacy for controlling two annual bluegrass phenotypes with target-site resistance to photosystem II (PSII) or enolpyruvylshikimate-3-phosphate synthase (EPSPS)-inhibiting herbicides (i.e., glyphosate), as well as phenotypes with multiple resistance to microtubule and EPSPS or PSII and acetolactate synthase (ALS)-inhibiting herbicides. All resistant phenotypes were established in glasshouse culture along with a known herbicide-susceptible control and treated with methiozolin at 0, 125, 250, 500, 1000, 2000, 4000, or 8000 g ai ha−1. Methiozolin effectively controlled annual bluegrass with target-site resistance to inhibitors of EPSPS, PSII, as well as multiple resistance to EPSPS and microtubule inhibitors. Methiozolin rates required to reduce aboveground biomass of these resistant phenotypes 50% (GR50 values) were not significantly different from the susceptible control, ranging from 159 to 421 g ha−1. A phenotype with target-site resistance to PSII and ALS inhibitors was less sensitive to methiozolin (GR50=862 g ha−1) than a susceptible phenotype (GR50=423 g ha−1). Our findings indicate that methiozolin is an effective option for controlling select annual bluegrass phenotypes with target-site resistance to several herbicides.

scholarly journals Herbicide Resistance and Management Options of Papaver rhoeas L. and Centaurea cyanus L. in Europe: A Review

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 874
Author(s):  
Marta Stankiewicz-Kosyl ◽  
Agnieszka Synowiec ◽  
Małgorzata Haliniarz ◽  
Anna Wenda-Piesik ◽  
Krzysztof Domaradzki ◽  
...  
Keyword(s):  
Herbicide Resistance ◽  
Acetolactate Synthase ◽  
Agricultural Landscapes ◽  
Target Site ◽  
Management Options ◽  
Papaver Rhoeas ◽  
Herbicide Resistant ◽  
Mediterranean Countries ◽  
Centaurea Cyanus ◽  
Target Site Resistance

Corn poppy (Papaver rhoeas L.) and cornflower (Centaurea cyanus L.) are two overwintering weed species found in crop fields in Europe. They are characterised by a similar life cycle, similar competitive efforts, and a spectrum of herbicides recommended for their control. This review summarises the biology and herbicide resistance phenomena of corn poppy and cornflower in Europe. Corn poppy is one of the most dangerous dicotyledonous weeds, having developed herbicide resistance to acetolactate synthase inhibitors and growth regulators, especially in Mediterranean countries and Great Britain. Target site resistance to acetolactate synthase inhibitors dominates among herbicide-resistant poppy biotypes. The importance of non-target site resistance to acetolactate synthase inhibitors in this species may be underestimated because non-target site resistance is very often associated with target site resistance. Cornflower, meanwhile, is increasingly rare in European agricultural landscapes, with acetolactate synthase inhibitors-resistant biotypes only listed in Poland. However, the mechanisms of cornflower herbicide resistance are not well recognised. Currently, herbicides mainly from acetolactate synthase and photosystem II inhibitors as well as from synthetic auxins groups are recommended for the control of both weeds. Integrated methods of management of both weeds, especially herbicide-resistant biotypes, continue to be underrepresented.

scholarly journals First Detection and Characterization of Cross- and Multiple Resistance to Acetyl-CoA Carboxylase (ACCase)- and Acetolactate Synthase (ALS)-Inhibiting Herbicides in Black-Grass (Alopecurus myosuroides) and Italian Ryegrass (Lolium multiflorum) Populations from Ireland

Agriculture ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1272
Author(s):  
Vijaya Bhaskar Alwarnaidu Vijayarajan ◽  
Patrick D Forristal ◽  
Sarah K Cook ◽  
David Schilder ◽  
Jimmy Staples ◽  
...  
Keyword(s):  
Lolium Multiflorum ◽  
Acetolactate Synthase ◽  
Target Site ◽  
Italian Ryegrass ◽  
Integrated Weed Management ◽  
Multiple Resistance ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Alopecurus Myosuroides ◽  
Target Site Resistance

Understanding the resistance spectrum and underlying genetic mechanisms is critical for managing herbicide-resistant populations. In this study, resistance to acetyl CoA carboxylase (ACCase) and acetolactate synthase (ALS) inhibitors was investigated in four suspected resistant populations of Alopecurus myosuroides (ALOMY-001 to ALOMY-004) and Lolium multiflorum (LOLMU-001 to LOLMU-004), collected from cereal production fields in Ireland. Glasshouse assays with three ALOMY-active herbicides [propaquizafop, cycloxydim (ACCase) and mesosulfuron + iodosulfuron (ALS)] or five LOLMU-active herbicides [pinoxaden, propaquizafop, cycloxydim (ACCase) and mesosulfuron + iodosulfuron, pyroxsulam (ALS)], and target-site resistance mechanism studies, based on pyrosequencing, were carried out in each of those populations. For A. myosuroides, Ile-1781-Leu ACCase mutation contributed to propaquizafop and cycloxydim resistance (shoot dry weight GR50 resistance factor (RF) = 7.5–35.5) in all ALOMY populations, and the independent Pro-197-Thr or Pro-197-Ser ALS mutation contributed to mesosulfuron + iodosulfuron resistance (RF = 3.6–6.6), in ALOMY-002 to ALOMY-004. Most of the analyzed plants for these mutations were homo/heterozygous combinations or only heterozygous. For L. multiflorum, phenotypic resistance to mesosulfuron + iodosulfuron (RF = 11.9–14.6) and pyroxsulam (RF = 2.3–3.1) was noted in all LOLMU populations, but the Pro-197-Gln or Pro-197-Leu ALS mutation (mostly in homozygous status) was identified in LOLMU-001, LOLMU-002 and LOLMU-004 only. Additionally, despite no known ACCase mutations in any LOLMU populations, LOLMU-002 survived pinoxaden and propaquizafop application (RF = 3.4 or 1.3), and LOLMU-003 survived pinoxaden (RF = 2.3), suggesting the possibility of non-target-site resistance mechanisms for ACCase and/or ALS resistance in these populations. Different resistance levels, as evidenced by a reduction in growth as dose increased above field rates in ALOMY and LOLMU, were due to variations in mutation rate and the level of heterozygosity, resulting in an overall resistance rating of low to moderate. This is the first study confirming cross- and multiple resistance to ACCase- and ALS-inhibiting herbicides, highlighting that resistance monitoring in A. myosuroides and L. multiflorum in Ireland is critical, and the adoption of integrated weed management strategies (chemical and non-chemical/cultural strategies) is essential.

Detecting Annual Bluegrass (Poa annua) Resistance to ALS-Inhibiting Herbicides Using a Rapid Diagnostic Assay

Weed Science ◽  
2013 ◽  
Vol 61 (3) ◽  
pp. 384-389 ◽  
Author(s):  
Robert B. Cross ◽  
Lambert B. McCarty ◽  
Nishanth Tharayil ◽  
Ted Whitwell ◽  
William C. Bridges
Keyword(s):  
South Carolina ◽  
Dose Response ◽  
Acetolactate Synthase ◽  
Shoot Biomass ◽  
Future Research ◽  
Clemson University ◽  
Herbicide Resistant ◽  
Annual Bluegrass ◽  
Als Inhibitors

Annual bluegrass is the most problematic winter annual weed in managed turfgrass. Acetolactate synthase (ALS)-inhibiting herbicides are effective for annual bluegrass control, but reliance on this mode of action can select for herbicide-resistant biotypes. Two annual bluegrass biotypes not controlled with ALS-inhibiting herbicides were reported at golf courses in South Carolina and Georgia. Research was initiated at Clemson University to verify the level of resistance of these biotypes to ALS inhibitors. Two ALS-susceptible (S) and suspected resistant (SCr, GAr) annual bluegrass biotypes were established in a greenhouse. Dose-response experiments were conducted on mature annual bluegrass plants using trifloxysulfuron, foramsulfuron, and bispyribac-sodium, all ALS-inhibiting herbicides. Additionally, a rapid diagnostic ALS activity assay was optimized and conducted using the same herbicides. For dose-response experiments, the rate of herbicide that reduced shoot biomass 50% (I50) values for the S biotypes were 13.6 g ai ha−1for trifloxysulfuron, 7.0 g ai ha−1for foramsulfuron, and 38.3 g ai ha−1for bispyribac-sodium. Fifty percent shoot biomass reduction was not observed in either the SCr or GAr biotypes at eight times the labeled field rate of all ALS-inhibiting herbicides tested. For in vivo tests of ALS activity, the SCr biotype yielded I50(concentration of herbicide that reduced ALS activity 50%) values 3,650, 3,290, and 13 times the S biotypes following treatment with trifloxysulfuron, foramsulfuron, and bispyribac-sodium, respectively. Similarly, I50values for the GAr biotype were 316, 140, and 64 times greater than the S biotypes following the same herbicide treatments. This research indicates high levels of annual bluegrass resistance to multiple ALS-inhibiting herbicides in South Carolina and Georgia. Future research should focus on the mechanisms of ALS resistance in these annual bluegrass biotypes as well as alternative options for control not targeting the ALS enzyme.

Modelling the Effectiveness of Herbicide Rotations and Mixtures as Strategies to Delay or Preclude Resistance

1990 ◽  
Vol 4 (1) ◽  
pp. 186-198 ◽  
Author(s):  
Jonathan Gressel ◽  
Lee A. Segel
Keyword(s):  
Enzyme System ◽  
Acetolactate Synthase ◽  
Cross Resistance ◽  
Competitive Fitness ◽  
Herbicide Resistant ◽  
Target Site Resistance ◽  
Herbicide Mixtures ◽  
Als Inhibitors ◽  
And Control ◽  
Single Enzyme

Herbicide-resistant populations have evolved only in monoculture and/or monoherbicide conditions at predictable rates for each compound and weed. No populations of triazine-resistant weeds have appeared in corn where rotations of crops and herbicides or herbicide mixtures were used. This is due to the greatly reduced competitive fitness of the resistant individuals, which could be expressed only during rotational cycles, and also to the greater sensitivity of resistant individuals to other herbicides, pests, and control practices (“negative cross-resistance”). The model presented here describes how an understanding of all of these factors can provide strategies to decrease the frequency of the resistant individuals during rotation. Rotations or mixtures may not delay the rate of appearance of resistance to inhibitors of acetolactate synthase (ALS), where the fitness of resistant biotypes is claimed to be near normal. The best way to delay resistance to ALS inhibitors is to use those compounds with less persistence so that the selection pressure will be lowered. Too little is known about the frequency of resistance to other herbicides with target-site resistance–to dinitroanilines, to acetyl CoA carboxylase inhibitors, or to those situations where a single enzyme system confers resistance to a broad spectrum of seemingly unrelated herbicides.

scholarly journals A Statewide Survey of PPO-Inhibitor Resistance and the Prevalent Target-Site Mechanisms in Palmer amaranth (Amaranthus palmeri) Accessions from Arkansas

Weed Science ◽  
2017 ◽  
Vol 66 (2) ◽  
pp. 149-158 ◽  
Author(s):  
Vijay K. Varanasi ◽  
Chad Brabham ◽  
Jason K. Norsworthy ◽  
Haozhen Nie ◽  
Bryan G. Young ◽  
...  
Keyword(s):  
Resistance Mechanism ◽  
Acetolactate Synthase ◽  
Resistance Mechanisms ◽  
Palmer Amaranth ◽  
Target Site ◽  
Evolution Of Resistance ◽  
Target Site Resistance ◽  
Novel Target ◽  
Als Inhibitors ◽  
Inhibitor Resistance

Palmer amaranth is one of the most problematic weeds in the midsouthern United States, and the evolution of resistance to protoporphyrinogen oxidase (PPO) inhibitors in biotypes already resistant to glyphosate and acetolactate synthase (ALS) inhibitors is a major cause of concern to soybean and cotton growers in these states. A late-season weed-escape survey was conducted in the major row crop–producing counties (29 counties) to determine the severity of PPO-inhibitor resistance in Arkansas. A total of 227 Palmer amaranth accessions were sprayed with fomesafen at 395 g ha−1to identify putative resistant plants. A TaqMan qPCR assay was used to confirm the presence of the ΔG210 codon deletion or the R128G/M (homologous to R98 mutation in common ragweed) target-site resistance mechanisms in thePPX2gene. Out of the 227 accessions screened, 44 were completely controlled with fomesafen, and 16 had only one or two severely injured plants (≥98% mortality) when compared with the 1986 susceptible check (100% mortality). The remaining 167 accessions were genotypically screened, and 82 (49%) accessions were found to harbor the ΔG210 deletion in thePPX2gene. The R128G was observed in 47 (28%) out of the 167 accessions screened. The mutation R128M, on the other hand was rare, found in only three accessions. About 13% of the accessions were segregating for both the ΔG210 and R128G mutations. Sixteen percent of the tested accessions had mortality ratings <90% and did not test positive for the ΔG210 or the R128G/M resistance mechanisms, indicating that a novel target or non–target site resistance mechanism is likely. Overall, PPO inhibitor–resistant Palmer amaranth is widespread in Arkansas, and the ΔG210 resistance mechanism is especially dominant in the northeast corridor, while the R128G mutation is more prevalent in counties near Memphis, TN.

Multiple resistance to PPO and ALS inhibitors in redroot pigweed (Amaranthus retroflexus)

Weed Science ◽  
2019 ◽  
pp. 1-8
Author(s):  
Hao Wang ◽  
Hengzhi Wang ◽  
Ning Zhao ◽  
Baolin Zhu ◽  
Penglei Sun ◽  
...  
Keyword(s):  
Resistance Mechanism ◽  
Resistance Index ◽  
Acetolactate Synthase ◽  
Amaranthus Retroflexus ◽  
Target Site ◽  
Multiple Resistance ◽  
Redroot Pigweed ◽  
First Case ◽  
Als Inhibitors

Abstract A redroot pigweed (Amaranthus retroflexus L.) population (HN-02) collected from Nenjiang County, Heilongjiang Province, exhibited multiple resistance to fomesafen and nicosulfuron. The purposes of this study were to characterize the herbicide resistance status of an HN-02 population for both acetolactate synthase (ALS) and protoporphyrinogen oxidase (PPO) inhibitors and the response to other herbicides and to investigate the target site-based mechanism governing fomesafen and nicosulfuron resistance. Three mutations, Ala-205-Val and Trp-574-Leu mutations in the ALS gene and an Arg-128-Gly mutation in the PPX2 gene, were identified in individual resistant plants. An HN-02F1-1 subpopulation homozygous for the Ala-205-Val and Arg-128-Gly mutations was generated, and whole-plant experiments confirmed multiple resistance to PPO inhibitors (fomesafen, fluoroglycofen-ethyl, and acifluorfen) and ALS inhibitors (imidazolinones [IMI], sulfonylureas [SU], and triazolopyrimidines [TP]) in the HN-02F1-1 plants, which presented resistance index values ranging from 8.3 to 110; however, these plants were sensitive to flumioxazin, fluroxypyr-meptyl, and 2,4-D butylate. In vitro ALS enzyme activity assays revealed that, compared with ALS from susceptible plants, ALS from the HN-02F1-1 plants was 15-, 28- and 320-fold resistant to flumetsulam, nicosulfuron, and imazethapyr, respectively. This study confirms the first case of multiple resistance to PPO and ALS inhibitors in A. retroflexus and determines that the target-site resistance mechanism was produced by Ala-205-Val and Arg-128-Gly mutations in the ALS gene and PPX2 gene, respectively. In particular, the Ala-205-Val mutation was found to endow resistance to three classes of ALS inhibitors: TP, SU, and IMI.

scholarly journals Target-site Mutation and Fitness Cost of Acetolactate Synthase Inhibitor-resistant Annual Bluegrass

HortScience ◽  
2019 ◽  
Vol 54 (4) ◽  
pp. 701-705
Author(s):  
Te-Ming Tseng ◽  
Swati Shrestha ◽  
James D. McCurdy ◽  
Erin Wilson ◽  
Gourav Sharma
Keyword(s):  
Dna Sequencing ◽  
Acetolactate Synthase ◽  
Target Site ◽  
Alternative Methods ◽  
Resistance Level ◽  
Annual Bluegrass ◽  
Mechanism Of Resistance ◽  
Als Inhibitors ◽  
Inhibitor Resistance ◽  
Als Inhibitor

Annual bluegrass (Poa annua L.) is an annual weed that is particularly troublesome in managed turfgrass. It has been controlled conventionally with herbicides, including acetolactate synthase (ALS) inhibitors. However, resistance to ALS inhibitors has been documented throughout the southeastern United States since 2012. A rate–response trial was conducted to confirm and determine the resistance level of suspected resistant P. annua biotypes from Mississippi (Reunion), followed by DNA sequencing to determine whether the mechanism of resistance is a target-site mutatio n. In addition, a fitness assay was conducted together with a susceptible biotype to determine whether resistance to ALS inhibitors is associated with decreased fitness. Reunion was at least 45 times more resistant to foramsulfuron than the standard susceptible biotype based on I50 estimates [I50 is the rate of herbicide giving a 50% response (50% visual necrosis)], requiring a predicted 331 g a.i./ha foramsulfuron for 50% control. DNA sequencing results identified a Trp574-to-Leu mutation in the ALS gene of the Reunion biotype, which has been shown by other studies to confer resistance to ALS inhibitors. Measurement of fitness parameters among the Reunion and susceptible biotypes demonstrated reduced seed yield, tillering, and flowering time in the resistant Reunion biotype, suggesting that ALS inhibitor resistance is possibly correlated to decreased fitness in P. annua. Alternative methods to control P. annua need to be considered as a result of the evolution of herbicide-resistant biotypes. An integrated management strategy to control P. annua weeds will help prevent further evolution of resistance. Because this study evaluated only the target-site mechanism of resistance, it is also necessary to determine whether the resistant biotype has reduced uptake, translocation, or enhanced metabolism as additional mechanisms of resistance. Consequently, a fitness study encompassing a more comprehensive list of plant parameters will provide conclusions of the fitness costs associated with ALS inhibitor resistance in P. annua. Chemical names: Foramsulfuron {1-(4,6-dimethoxypyrimidin-2-yl)-3-[2-(dimethylcarbamoyl)-5-formamidophenylsulfonyl] urea}.

Target site–based resistance to penoxsulam in late watergrass (Echinochloa phyllopogon) from China

Weed Science ◽  
2019 ◽  
Vol 67 (4) ◽  
pp. 380-388 ◽  
Author(s):  
Jian Liu ◽  
Jiapeng Fang ◽  
Zongzhe He ◽  
Jun Li ◽  
Liyao Dong
Keyword(s):  
Binding Affinity ◽  
Acetolactate Synthase ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Future Research ◽  
Target Site Resistance ◽  
Target Gene Sequence ◽  
Als Inhibitors ◽  
Echinochloa Phyllopogon

AbstractLate watergrass [Echinochloa phyllopogon (Stapf) Koso-Pol.] is one of the most persistent weeds in rice fields and shows resistance to some acetolactate synthase (ALS)-inhibiting herbicides, such as penoxsulam. Previous studies of E. phyllopogon’s herbicide resistance have focused on non–target site resistance mechanisms. In this study, E. phyllopogon populations from Heilong Jiang Province, China, that were possibly resistant to penoxsulam were used to identify the target site–based mechanisms of resistance. Population HSRH-520 showed a 25.4-fold higher resistance to penoxsulam than the sensitive population, HSRH-538. HSRH-520 was resistant to other ALS inhibitors, with resistance indexes ranging from 17.1 to 166. Target-gene sequence analysis revealed two different ALS genes in E. phyllopogon; a Pro-197-Ser substitution occurred in the ALS-2 gene of HSRH-520. In vitro activity assays revealed that the penoxsulam concentrations required to inhibit 50% of the ALS activity were 13.7 times higher in HSRH-520 than in HSRH-538. Molecular-docking tests showed that the Pro-197-Ser mutation reduced the binding affinity between ALS and ALS inhibitors belonging to the triazolopyrimidine, sulfonylaminocarbonyltriazolinone, and sulfonylurea families, and there were almost no effects on binding affinity when the ALS inhibitors were of the pyrimidinylthiobenzoate and imidazolinone families. Overall, the results indicated and verified that the Pro-197-Ser mutation leads to increased ALS activity by reducing the binding affinity of the inhibitor and ALS. This is the first report on the Pro-197-Ser mutation in the complete ALS gene of E. phyllopogon and will aid future research of target site–based resistance mechanisms of E. phyllopogon to ALS inhibitors.

Investigating the resistance levels and mechanisms to penoxsulam and cyhalofop-butyl in barnyardgrass (Echinochloa crus-galli) from Ningxia province, China

Weed Science ◽  
2021 ◽  
pp. 1-25
Author(s):  
Qian Yang ◽  
Xia Yang ◽  
Zichang Zhang ◽  
Jieping Wang ◽  
Weiguo Fu ◽  
...  
Keyword(s):  
Herbicide Resistance ◽  
Molecular Mechanisms ◽  
Acetolactate Synthase ◽  
Rice Fields ◽  
Target Site ◽  
Herbicide Resistant ◽  
Susceptible Populations ◽  
High Level ◽  
Als Inhibitor ◽  
Encoding Genes

Abstract Barnyardgrass (Echinochloa crus-galli) is a noxious grass weed which infests rice fields and causes huge crop yield losses. In this study, we collected twelve E. crus-galli populations from rice fields of Ningxia province in China and investigated the resistance levels to acetolactate synthase (ALS) inhibitor penoxsulam and acetyl-CoA carboxylase (ACCase) inhibitor cyhalofop-butyl. The results showed that eight populations exhibited resistance to penoxsulam and four populations evolved resistance to cyhalofop-butyl. Moreover, all of the four cyhalofop-butyl-resistant populations (NX3, NX4, NX6 and NX7) displayed multiple-herbicide-resistance (MHR) to both penoxsulam and cyhalofop-butyl. The alternative herbicides bispyribac-sodium, metamifop and fenoxaprop-P-ethyl cannot effectively control the MHR plants. To characterize the molecular mechanisms of resistance, we amplified and sequenced the target-site encoding genes in resistant and susceptible populations. Partial sequences of three ALS genes and six ACCase genes were examined. A Trp-574-Leu mutation was detected in EcALS1 and EcALS3 in two high-level (65.84- and 59.30-fold) penoxsulam-resistant populations NX2 and NX10, respectively. In addition, one copy (EcACC4) of ACCase genes encodes a truncated aberrant protein due to a frameshift mutation in E. crus-galli populations. None of amino acid substitutions that are known to confer herbicide resistance were detected in ALS and ACCase genes of MHR populations. Our study reveals the widespread of multiple-herbicide resistant E. crus-galli populations at Ningxia province of China that exhibit resistance to several ALS and ACCase inhibitors. Non-target-site based mechanisms are likely to be involved in E. crus-galli resistance to the herbicides, at least in four MHR populations.

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