Confirmation of Flixweed (Descurainia sophia) Resistance to Tribenuron-Methyl Using Three Different Assay Methods

Research was conducted to establish a method to investigate the resistance level of flixweed to tribenuron-methyl and the evolved biochemical resistance mechanism. Four resistant biotypes were collected from wheat fields in Mazhuangcun, Jiacun, Dishangcun, and Bafangcun in the Hebei province of China where tribenuron-methyl had been continuously used for more than 10 yr. Two susceptible biotypes were collected from wheat fields where tribenuron-methyl was never applied. Different biotypes were assessed by petri-dish bioassay, whole-plant bioassay, and acetolactate synthase (ALS) assay. Comparisons of data indicated a similarity between methods and that experiments demonstrated that petri-dish bioassay was a feasible method to identify flixweed resistant to tribenuron-methyl. Data indicated differences among the flixweed biotypes when assessed by the petri-dish bioassay, whole-plant bioassay, or ALS enzyme assay, and a close association was obtained for the three bioassay methods. ALS resistance varied by biotypes with Mazhuangcun > Jiacun > Dishangcun > Bafangcun. Target-site enzyme assay data indicated that the resistant biotype's enhanced ALS activity was the biochemical mechanism that induced flixweed's evolved resistance to tribenuron-methyl. The concentrations of tribenuron-methyl causing 50% inhibition of ALS activity of the four resistant biotypes were 1,359, 513, 184, and 164 nM; in the susceptible biotypes these concentrations were 64 and 65 nM. Resistance indexes were 21, 8, 3, and 3 for Mazhuangcun, Jiacun, Dishangcun, and Bafangcun biotypes, respectively.

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Acetolactate Synthase Gene Proline (197) Mutations Confer Tribenuron-Methyl Resistance in Flixweed (Descurainia sophia) Populations from China

Weed Science ◽

10.1614/ws-d-10-00099.1 ◽

2011 ◽

Vol 59 (3) ◽

pp. 376-379 ◽

Cited By ~ 28

Author(s):

Hai Lan Cui ◽

Chao Xian Zhang ◽

Shou Hui Wei ◽

Hong Jun Zhang ◽

Xiang Ju Li ◽

...

Keyword(s):

Amino Acid ◽

Molecular Basis ◽

Resistance Mechanism ◽

Point Mutations ◽

Acetolactate Synthase ◽

Amino Acid Position ◽

Resistance Level ◽

Coding Sequence ◽

Whole Plant ◽

Tribenuron Methyl

The molecular basis of resistance to tribenuron-methyl, an acetolactate synthase (ALS)–inhibiting herbicide was investigated in four resistant (R) and three susceptible (S) flixweed populations. The resistance level in the R populations was assessed in whole-plant pot experiments in a greenhouse, and resistance indices ranged from 723 to 1422. The ALS genes of the three S populations and four R populations were cloned and sequenced, and the full coding sequence of the ALS gene of flixweed was 2,004 bp. The sequences of the ALS genes of the three S populations collected from Shaanxi, Gansu, and Tianjin were identical. Comparison of the ALS gene sequences of the S and R populations withArabidopsisrevealed that proline at position 197 of the ALS gene was substituted by leucine in R population SSX-2, by alanine in R population SSX-3, and by serine in R populations TJ-2 and GS-2. In another study of two R flixweed populations from Hebei and Shaanxi, resistance was also related to mutation at position 197 of the ALS gene. Both studies confirmed tribenuron-methyl resistance in flixweed in China, with the resistance mechanism being conferred by specific ALS point mutations at amino acid position 197.

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Continuous Use of Tribenuron-Methyl Selected for Cross-Resistance to Acetolactate Synthase–inhibiting Herbicides in Wild Mustard (Sinapis arvensis)

Weed Science ◽

10.1017/wsc.2018.23 ◽

2018 ◽

Vol 66 (4) ◽

pp. 424-432 ◽

Cited By ~ 4

Author(s):

Javid Gherekhloo ◽

Zahra M. Hatami ◽

Ricardo Alcántara-de la Cruz ◽

Hamid R. Sadeghipour ◽

Rafael De Prado

Keyword(s):

Winter Wheat ◽

Acetolactate Synthase ◽

Dry Weight ◽

Resistance Mechanisms ◽

Cross Resistance ◽

Resistance Level ◽

Sinapis Arvensis ◽

Wild Mustard ◽

Golestan Province ◽

Tribenuron Methyl

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.

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Resistance in Smallflower Umbrella Sedge (Cyperus difformis L.) to Acetolactate Synthase-Inhibiting Herbicides in Rice - First Case in India

Weed Technology ◽

10.1017/wet.2021.73 ◽

2021 ◽

pp. 1-22

Author(s):

Vijay K. Choudhary ◽

Seshadri S. Reddy ◽

Subhash K. Mishra ◽

Bhumesh Kumar ◽

Yogita Gharde ◽

...

Keyword(s):

Enzyme Activity ◽

Acetolactate Synthase ◽

Activity Assay ◽

Enzyme Activity Assay ◽

Synthetic Auxin ◽

Cyperus Difformis ◽

First Case ◽

Whole Plant ◽

Plant Bioassay ◽

Direct Seeded

Abstract Smallflower umbrella sedge is one of the problematic weeds in direct-seeded rice in India. Bispyribac-sodium (acetolactate synthase-inhibiting herbicide) is a commonly used in rice, but recently growers have reported lack of smallflower umbrella sedge control with this herbicide. An extensive survey was carried out in two rice growing states, Chhattisgarh and Kerala, where 53 putative bispyribac-sodium resistant (BR) biotypes were collected. Studies were conducted to confirm resistance to bispyribac-sodium and to test the efficacy of newly developed synthetic auxin herbicide florpyrauxifen-benzyl on putative BR biotypes. Whole-plant bioassay revealed that bispyribac-sodium is no longer effective. Of 53 putative BR biotypes, 17 biotypes survived recommended label rate of 25 g ai ha−1. Effective bispyribac-sodium rate required to control 50% of the plants in most of the BR biotypes (ED50) ranged from 19 to 96 g ha−1 whereas it was 10 g ha−1 in susceptible biotype. In two highly resistant biotypes, ED50 was beyond the maximum tested rate, 200 g ha−1. This suggests 2 to >20-fold resistance in BR biotypes. Acetolactate synthase (ALS) enzyme activity assay suggests altered target site as mechanism of resistance to bispyribac-sodium. This study confirms the first case of evolved resistance in smallflower umbrella sedge for bispyribac-sodium in India. However, the newly developed synthetic auxin, florpyrauxifen-benzyl effectively controlled all BR biotypes at the field use rate 31.25 g ae ha−1.

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Acetolactate Synthase Resistance in a Common Waterhemp (Amaranthus rudis) Population

Weed Technology ◽

10.1017/s0890037x00041269 ◽

1997 ◽

Vol 11 (1) ◽

pp. 13-18 ◽

Cited By ~ 36

Author(s):

John R. R. Hinz ◽

Micheal D. K. Owen

Keyword(s):

Plant Material ◽

Resistance Mechanism ◽

Acetolactate Synthase ◽

Grain Amaranth ◽

Common Waterhemp ◽

Resistant Species ◽

Whole Plant ◽

Amaranthus Rudis ◽

Inhibitor Resistance ◽

Als Inhibitor

Research was initiated to determine (a) whether a common waterhemp population was resistant to acetolactate synthase (ALS) inhibiting herbicides, (b) the percentage of the population that was ALS-inhibitor resistant, (c) the resistance mechanism, and (d) the effectiveness of a whole plant assay to detect ALS-inhibitor resistance. ALS-inhibitor resistance was confirmed in a common waterhemp population near Davis City, IA. The Davis City common waterhemp population was cross resistant to both imidazolinone and sulfonylurea herbicides, but not to lactofen. Approximately 10% of the Davis City common waterhemp population was sensitive to a rate of imazaquin 4 times the normal field rate. Davis City common waterhemp isolated ALS was much less sensitive to imazaquin and primisulfuron inhibition than was grain amaranth or an ALS-sensitive common waterhemp isolated ALS. Imazaquin I50values were 366.4 and 3.4 μM for ALS isolated from Davis City common waterhemp and grain amaranth, respectively. Primisulfuron I50values were 3.6 and 0.007 μM for ALS isolated from Davis City common waterhemp and grain amaranth, respectively. A whole plant ALS assay was developed that allowed for much more rapid detection of an ALS-resistant species and used less plant material than a conventional ALS assay.

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Multiple herbicide resistance in California Italian ryegrass (Lolium perenne ssp. multiflorum): characterization of ALS-inhibiting herbicide resistance

Weed Science ◽

10.1017/wsc.2019.1 ◽

2019 ◽

Vol 67 (3) ◽

pp. 273-280 ◽

Cited By ~ 4

Author(s):

Parsa Tehranchian ◽

Vijay K. Nandula ◽

Maor Matzrafi ◽

Marie Jasieniuk

Keyword(s):

Lolium Perenne ◽

Herbicide Resistance ◽

Resistance Mechanism ◽

Acetolactate Synthase ◽

Target Site ◽

Italian Ryegrass ◽

Resistance Level ◽

Als Inhibitors ◽

Inhibitor Resistance ◽

Als Inhibitor

AbstractMultiple resistance to glyphosate, sethoxydim, and paraquat was previously confirmed in two Italian ryegrass [Lolium perenne L. ssp. multiflorum (Lam.) Husnot] populations, MR1 and MR2, in northern California. Preliminary greenhouse studies revealed that both populations were also resistant to imazamox and mesosulfuron, both of which are acetolactate synthase (ALS)-inhibiting herbicides. In this study, three subpopulations, MR1-A (from seed of MR1 plants that survived a 16X rate of sethoxydim), MR1-P (from seed of MR1 plants that survived a 2X rate of paraquat), and MR2 (from seed of MR2 plants that survived a 16X rate of sethoxydim), were investigated to determine the resistance level to imazamox and mesosulfuron, evaluate other herbicide options for the control of these multiple resistant L. perenne ssp. multiflorum, and characterize the underlying ALS-inhibitor resistance mechanism(s). Based on LD50 values, the MR1-A, MR1-P, and MR2 subpopulations were 38-, 29-, 8-fold and 36-, 64-, and 3-fold less sensitive to imazamox and mesosulfuron, respectively, relative to the susceptible (Sus) population. Only MR1-P and MR2 plants were cross-resistant to rimsulfuron, whereas both MR1 subpopulations were cross-resistant to imazethapyr. Pinoxaden (ACCase inhibitor [phenylpyrazoline 'DEN']) only controlled MR2 and Sus plants at the labeled field rate. However, all plants were effectively controlled (>99%) with the labeled field rate of glufosinate. Based on I50 values, MR1-A, MR-P, and MR2 plants were 712-, 1,104-, and 3-fold and 10-, 18-, and 5-fold less responsive to mesosulfuron and imazamox, respectively, than the Sus plants. Sequence alignment of the ALS gene of resistant plants revealed a missense single-nucleotide polymorphism resulting in a Trp-574-Leu substitution in MR1-A and MR1-P plants, heterozygous in both, but not in the MR2 plants. An additional homozygous substitution, Asp-376-Glu, was identified in the MR1-A plants. Addition of malathion or piperonyl butoxide did not alter the efficacy of mesosulfuron on MR2 plants. In addition, the presence of 2,4-D had no effect on the response of mesosulfuron on the MR2 and Sus. These results suggest an altered target site is the mechanism of resistance to ALS inhibitors in MR1-A and MR1-P plants, whereas a non–target site based resistance apparatus is present in the MR2 plants.

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Resistance Mechanism to Tribenuron-Methyl in White Mustard (Sinapis alba) from Southern Spain

Weed Science ◽

10.1614/ws-d-12-00146.1 ◽

2013 ◽

Vol 61 (3) ◽

pp. 341-347 ◽

Cited By ~ 15

Author(s):

Hugo Cruz-Hipolito ◽

Jesus Rosario ◽

Gerardina Ioli ◽

Maria D. Osuna ◽

Reid J. Smeda ◽

...

Keyword(s):

Resistance Mechanism ◽

Acetolactate Synthase ◽

Southern Spain ◽

Cereal Crops ◽

Laboratory Studies ◽

White Mustard ◽

Site Mutation ◽

Gene Encoding ◽

Layer Chromatography ◽

Tribenuron Methyl

Tribenuron-methyl has been used widely for the last 15 yr to control white mustard in cereal crops from southern Spain. Since 2007, several cases of tribenuron-methyl resistance have been reported in wheat fields. Greenhouse and laboratory studies were conducted to characterize the mechanism of suspected tribenuron-methyl resistance in a white mustard biotype (hereafter AR16) from Malaga (southern Spain). Under greenhouse conditions, the dose (g ai ha−1) inhibiting fresh weight by 50% (ED50) was 5.20 and 0.57 for the AR16and AR3(known susceptible) biotypes, respectively. With the use of14C-tribenuron-methyl, absorption and translocation from treated leaves were similar between biotypes. Thin-layer chromatography indicated foliar metabolism of tribenuron-methyl was low in both R and S biotypes. Assays on the binding affinity of tribenuron-methyl on acetolactate synthase (ALS) revealed enzyme activity was reduced by 50% (I50value) at 638.7 and 0.23 nM for the AR16and AR3biotypes, respectively. This resulted in 2,777-fold greater resistance to tribenuron-methyl for the AR16compared to AR3biotype. Sequencing the gene encoding ALS, a proline/serine amino-acid substitution, was detected in position 197 of the A domain. Based on these results, it is concluded that tribenuron-methyl resistance in the AR16biotype is due to a target-site mutation in the ALS enzyme, resulting in a lack of affinity to tribenuron-methyl.

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ALS Gene Mutations in Apera Spica-Venti Confer Broad-Range Resistance to Herbicides

Journal of Plant Protection Research ◽

10.2478/v10045-011-0043-7 ◽

2011 ◽

Vol 51 (3) ◽

pp. 261-267 ◽

Cited By ~ 9

Author(s):

Michał Krysiak ◽

Stanisław Gawroński ◽

Kazimierz Adamczewski ◽

Roman Kierzek

Keyword(s):

Gene Mutations ◽

Pcr Amplification ◽

Acetolactate Synthase ◽

Nucleotide Polymorphisms ◽

Molecular Tests ◽

Whole Plant ◽

Plant Bioassay ◽

Resistance To Herbicides ◽

Als Inhibitors ◽

High Level

ALS Gene Mutations in Apera Spica-Venti Confer Broad-Range Resistance to Herbicides Several biotypes of wind bentgrass in Poland have been identified as being resistant to acetolactate synthase (ALS) inhibitors. We screened these weeds with chlorsulfuron and performed a whole-plant bioassay with a range of doses based on these four herbicides: chlorsulfuron, sulfosulfuron, propoxycarbazone-sodium and mesosulfuron-methyl + iodosulfuron-methyl-sodium mixture. Ten biotypes, diverse in their levels of resistance, were submitted for molecular tests. PCR amplification and sequencing of als domains demonstrated numerous single nucleotide polymorphisms. Nine biotypes showed non-synonymous substitutions in codon Pro197, changing it to Ser or Thr. Mutation in Pro197 conferred a high level of resistance to the tested herbicides. Analysis of four biotypes also revealed a substitution in the Ala122 codon, changing it to Val. In one biotype this substitution was not accompanied by Pro197 mutation and this biotype was resistant to chlorsulfuron and mesosulfuron + iodosulfuron, but not to sulfosulfuron or propoxycarbazone-sodium. Correspondence between mutations and levels of resistan ce to ALS inhibitors may support management of resistant weeds with the existing palette of herbicides.

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The First Case of Short-Spiked Canarygrass (Phalaris brachystachys) with Cross-Resistance to ACCase-Inhibiting Herbicides in Iran

Agronomy ◽

10.3390/agronomy9070377 ◽

2019 ◽

Vol 9 (7) ◽

pp. 377

Author(s):

Sajedeh Golmohammadzadeh ◽

Javid Gherekhloo ◽

Antonia M. Rojano-Delgado ◽

M. Dolores Osuna-Ruíz ◽

Behnam Kamkar ◽

...

Keyword(s):

Rapid Test ◽

Cross Resistance ◽

Cytochrome P450 Monooxygenases ◽

Resistance Level ◽

Winter Cereal ◽

P450 Monooxygenases ◽

First Case ◽

Whole Plant ◽

Plant Bioassay ◽

Golestan Province

The weed Phalaris brachystachys Link. severely affects winter cereal production. Acetyle-CoA Carboxylase (ACCase)-inhibiting herbicides are commonly used to control this weed in wheat fields. Thirty-six populations with suspected resistance to ACCase-inhibiting herbicides were collected from wheat fields in the Golestan Province in Iran. A rapid test performed in Petri dishes and whole-plant dose–response experiments were conducted to confirm and investigate the resistance level of P. brachystachys to ACCase-inhibiting herbicides. The seed bioassay results showed that 0.02 mg ai L−1 clodinafop-propargyl (CP) and 1.36 mg ai L−1 of the diclofop-methyl (DM) solution were the optimal amounts for reliably screening resistant and susceptible P. brachystachys populations. In the whole plant bioassay, all populations were found to be resistant to CP, resistance ratios ranging from 2.7 to 11.6, and all of the CP-resistant populations exhibited resistance to DM. Fourteen populations showed low resistance to cycloxydim, and thirteen of these populations were also 2-fold resistant to pinoxaden. The results showed that DM resistance in some P. brachystachys populations is likely due to their enhanced herbicide metabolism, which involves Cytochrome P450 monooxygenases, as demonstrated by the indirect assay. This is the first report confirming the cross-resistance of ACCase-inhibiting herbicides in P. brachystachys in Iran.

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Occurrence of Resistance to ALS Inhibitors in European Cyperus esculentus L.: Characterisation and Implications for Management

Agronomy ◽

10.3390/agronomy10081133 ◽

2020 ◽

Vol 10 (8) ◽

pp. 1133

Author(s):

Laura Scarabel ◽

Silvia Farinati ◽

Maurizio Sattin

Keyword(s):

Resistance Mechanism ◽

Resistance Management ◽

Acetolactate Synthase ◽

Integrated Approach ◽

Invasive Weed ◽

Row Crops ◽

Yellow Nutsedge ◽

Agronomic Practices ◽

Whole Plant ◽

Als Inhibitors

Yellow nutsedge (C. esculentus) is a perennial geophyte and invasive weed which is very difficult to control in rice and other irrigated row crops. Acetolactate synthase (ALS) inhibitors are the most commonly used herbicides to control sedges in rice. Failure to control C. esculentus was recently reported in a rice field in north-western Italy. The resistance status of this C. esculentus population was determined through a whole-plant bioassay. The mechanism underlying the resistance was elucidated, and the available chemical and non-chemical control options were discussed. The population proved to be resistant to halosulfuron and azimsulfuron at the recommended field rate. The ALS trancripts amplified from resistant and susceptible plants revealed the presence of a Pro197-to-Arg amino acid substitution in resistant plants, indicating that the resistance mechanism is target-site mediated. This is the first confirmation of herbicide resistance in C. esculentus in Europe. Resistance management should be based on an integrated approach, through the combination of diversified cultural and agronomic practices that can limit its spread and propagation through tubers.

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Genetic Variability of Acetolactate Synthase (ALS) Sequence in Centaurea cyanus Plants Resistant and Susceptible to Tribenuron-Methyl

Agronomy ◽

10.3390/agronomy11112311 ◽

2021 ◽

Vol 11 (11) ◽

pp. 2311

Author(s):

Barbara Wrzesińska ◽

Tadeusz Praczyk

Keyword(s):

Amino Acid ◽

Genetic Variability ◽

Amino Acid Sequence ◽

Herbicide Resistance ◽

Resistance Mechanism ◽

Acetolactate Synthase ◽

Sequence Information ◽

Sequence Variability ◽

Centaurea Cyanus ◽

Tribenuron Methyl

Centaurea cyanus, belonging to the Asteraceae family, is an arable weed species encountered mainly in fields with cereals, sugar beet, and maize. The high genetic variability of C. cyanus has been recently reported; however, little is known about its sequence variability in the context of its herbicide resistance. C. cyanus resistance was found mainly against acetolactate synthase (ALS) inhibitors, but no ALS sequence information concerning the herbicide resistance mechanism has been published yet. The aim of this study was to determine the ALS sequences for biotypes susceptible and resistant to tribenuron-methyl in order to identify mutations that may be associated with the resistance emergence. DNA isolation from susceptible and resistant plants was followed by PCR amplification and ALS sequencing. As a result, different lengths of DNA products were obtained. Moreover, both nucleotide and amino acid sequence analysis revealed high sequence variability within one plant as well as between plants from the same biotype. In a few resistant plants, four changes in the amino acid sequence were identified in comparison to those in the susceptible ones. However, these preliminary studies require further investigation toward confirming the significance of these mutations in herbicide resistance development. This study provides preliminary information contributing to the research on the C. cyanus target-site resistance mechanism.

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