Rapid necrosis: a novel plant resistance mechanism to 2,4-D

Abstract Plants of Sumatran fleabane [Conyza sumatrensis (Retz.) E. Walker] were identified in a field with an unusual rapid leaf-injury herbicide symptoms after application of 2,4-D in mixture with glyphosate. The objectives of this study were to confirm the occurrence of resistance to 2,4-D herbicide and to characterize the occurrence of rapid necrosis as the mechanism associated with the herbicide resistance in C. sumatrensis. The studies performed were an initial screening, effect of 2,4-D alone and associated with glyphosate, cross- and multiple-resistance evaluation, effect of commercial formulation and analytical product, and rate of H2O2 evolution. The Marpr9-rn accession was identified with rapid necrosis symptoms and survival to 804 g ae ha−1 of 2,4-D. The resistance factor to the herbicide 2,4-D was 18.6 at 49 d after spraying. The analytical product 2,4-D and the commercial formulation resulted in similar symptoms of rapid necrosis. This symptom did not occur for the six other auxinic herbicides (dicamba, florpyrauxifen-benzyl, fluroxypyr, halauxifen-methyl, picloram, and triclopyr), indicating absence of cross-resistance. Multiple resistance to the herbicides paraquat, saflufenacil, and ammonium glufosinate was not identified in the Marpr9-rn population. However, survival following treatment with the herbicides glyphosate and chlorimuron-ethyl occurred. The evolution of H2O2 began at 15 min after application and was less pronounced in low light. These results indicate the first case of resistance to 2,4-D and occurrence of rapid necrosis in C. sumatrensis.

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MULTIPLE RESISTANCE OF Amaranthus palmeri TO ALS AND EPSPS INHIBITING HERBICIDES IN THE STATE OF MATO GROSSO, BRAZIL

Planta Daninha ◽

10.1590/s0100-83582016340300019 ◽

2016 ◽

Vol 34 (3) ◽

pp. 581-587 ◽

Cited By ~ 8

Author(s):

A. GONÇALVES NETTO ◽

M. NICOLAI ◽

S.J.P. CARVALHO ◽

E.A. BORGATO ◽

P.J. CHRISTOFFOLETI

Keyword(s):

The State ◽

Cross Resistance ◽

Multiple Resistance ◽

Amaranthus Palmeri ◽

Mato Grosso ◽

Chlorimuron Ethyl ◽

D 20 ◽

Chemical Groups

ABSTRACT This work was carried out in order to evaluate the susceptibility to ALS-inhibiting herbicides of the Brazilian biotype of glyphosate-resistant A. palmeri, considering different chemical groups. For that, four experiments were performed, each with one of the following herbicides: glyphosate, chlorimuron-ethyl, cloransulan-methyl and imazethapyr. In each trial, treatments were organized according to a 2x8 factorial scheme, in which two were the species of Amaranthus (A. palmeri and A. spinosus) and eight were the herbicide rates (16D, 8D, 4D, 2D, D, 1/2D, 1/4D and herbicide absence; being D the commercial rate of each product). For glyphosate, D = 720 g a.e. ha-1; for chlorimuron-ethyl, D = 20 g ha-1; for cloransulanmethyl, D = 30 g ha-1; for imazethapyr, D = 100 g ha-1. Glyphosate was not applied on A. spinosus. In all the trials, the Brazilian biotype of A. palmeri had low herbicide susceptibility, so it was possible to conclude this biotype has ALS-EPSPs multiple resistance. Therefore, considering only ALS-inhibiting herbicides, this population has sulfonilurea-triazolopirimidineimidazolinone cross-resistance.

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

Weed Science ◽

10.1017/wsc.2019.61 ◽

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.

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Multiple resistance to glyphosate and imazethapyr in Bidens subalternans

Ciência e Agrotecnologia ◽

10.1590/1413-7054201943009919 ◽

2019 ◽

Vol 43 ◽

Author(s):

Rafael Romero Mendes ◽

Fernando Storniolo Adegas ◽

Hudson Kagueyama Takano ◽

Vanessa Francieli Vital Silva ◽

Fellipe Goulart Machado ◽

...

Keyword(s):

Acetolactate Synthase ◽

Future Research ◽

Multiple Resistance ◽

Growing Seasons ◽

Ammonium Glufosinate ◽

First Case ◽

Rf Values ◽

Als Inhibitors ◽

Production Areas ◽

Control Failures

ABSTRACT Glyphosate has been widely used to control greater beggarticks populations that are resistant to acetolactate synthase (ALS) inhibitors in South America. However, herbicide control failures has been observed over the last three growing seasons in grain production areas of Paraguay. In this research, we report the first case of multiple resistance to glyphosate (EPSPs) and imazethapyr (ALS) in greater beggarticks (Bidens subalternans) population from Paraguay. This conclusion was supported by dose-response experiments conducted in two consecutive years (2018 and 2019) with a putative resistant (R) and a susceptible (S) population. Alternative herbicides were also tested for post-emergence control of R population. For glyphosate, the resistant factor (RF) values were 8.8- (2018) and 15.7-fold (2019). For imazethapyr, the RF values were 59- and 58-fold, in 2018 and 2019, respectively. Treatments with 2,4-D, dicamba, 2,4-D + glyphosate, dicamba + glyphosate, lactofen, fomesafen, ammonium-glufosinate, atrazine, and bentazon provided more than 80% control of the R population. This is the first case of multiple resistance to glyphosate and imazethapyr in greater beggarticks (Bidens subalternans) in the world. The mechanisms underlying resistance in this biotype should be evaluated in future research.

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Nontarget site resistance in Palmer amaranth [Amaranthus palmeri(S.) Wats.] confers cross-resistance to protoporphyrinogen oxidase-inhibiting herbicides

Weed Technology ◽

10.1017/wet.2019.12 ◽

2019 ◽

Vol 33 (2) ◽

pp. 349-354 ◽

Cited By ~ 6

Author(s):

Vijay K. Varanasi ◽

Chad Brabham ◽

Nicholas E. Korres ◽

Jason K. Norsworthy

Keyword(s):

Resistance Index ◽

Acetolactate Synthase ◽

Palmer Amaranth ◽

Cross Resistance ◽

Multiple Resistance ◽

Protoporphyrinogen Oxidase ◽

First Case ◽

Sites Of Action ◽

Als Inhibitor ◽

Biomass Reduction

AbstractPalmer amaranth is one of the most problematic weeds in cropping systems of North America, especially in midsouthern United States, because of its competitive ability and propensity to evolve resistance to several herbicide sites of action. Previously, we confirmed and characterized the first case of nontarget site resistance (NTSR) to fomesafen in a Palmer amaranth accession from Randolph County, AR (RCA). The primary basis of the present study was to evaluate the cross- and multiple-resistance profile of the RCA accession. The fomesafen dose-response assay in the presence of malathion revealed a lower level of RCA resistance when compared with fomesafen alone. The resistance index of the RCA accession, based on 50% biomass reduction, ranged from 63-fold (fomesafen alone) to 22-fold (malathion plus fomesafen), when compared with a 2007 susceptible, and 476-fold and 167-fold, respectively, relative to a 1986 susceptible check. The RCA accession was resistant to other protoporphyrinogen oxidase (PPO) inhibitors (i.e., flumioxazin, acifluorfen, saflufenacil) as well as the 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor tembotrione and acetolactate synthase (ALS) inhibitor pyrithiobac sodium. Sequencing of theALSgene revealed no point mutations, indicating that a target-site mechanism is not involved in conferring ALS-inhibitor resistance in the RCA accession. Of the three PPO-inhibiting herbicides tested in combination with the malathion, saflufenacil resulted in the greatest biomass reduction (80%;P< 0.05) and lowest survival rate (23%;P< 0.05) relative to nontreated plants. The application of cytochrome P450 or glutathioneS-transferase inhibitors with fomesafen did not lead to any adverse effects on soybean, suggesting a possible role for these compounds for management of NTSR under field conditions. These results shed light on the relative unpredictability of NTSR in conferring herbicide cross- and multiple resistance in Palmer amaranth.

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Lack of Cross-Resistance of Paraquat-Resistant Hairy Fleabane (Conyza bonariensis) to Other Toxic Oxygen Generators Indicates Enzymatic Protection is Not the Resistance Mechanism

Weed Science ◽

10.1017/s0043174500055764 ◽

1989 ◽

Vol 37 (1) ◽

pp. 5-11 ◽

Cited By ~ 28

Author(s):

Kevin C. Vaughn ◽

Martin A. Vaughan ◽

Patrick Camilleri

Keyword(s):

Electron Microscopy ◽

Chlorophyll Fluorescence ◽

Resistance Mechanism ◽

Cross Resistance ◽

Oxygen Generator ◽

Conyza Bonariensis ◽

Singlet Oxygen Generator ◽

Chlorophyll Bleaching ◽

Direct Measures ◽

Hairy Fleabane

Cross-resistance of the paraquat-resistant (R) hairy fleabane to other compounds that accept electrons from photosystem I (PSI) or produce toxic oxygen species was determined by chlorophyll loss, electron microscopy, and chlorophyll fluorescence suppression. Although the R bioype is approximately 100 x more resistant to paraquat than the susceptible (S) biotype based upon the assays for tissue damage, little or no cross-resistance was observed to a number of other PSI electron acceptors, including the bipyridilium herbicide morfamquat. A low level of resistance (approximately 10-fold) was noted to diquat and the singlet oxygen generator rose bengal. As measured by chlorophyll fluorescence suppression, the R biotype was about 100-fold resistant to paraquat, but only 10-fold resistant to diquat, and exhibited no resistance to morfamquat. Because differences observed with this protocol are direct measures of the ability of the herbicide to reach the active site and the results correlate with the level of resistance observed by chlorophyll bleaching or electron microscopy, these data suggest that compartmentalization is the major factor in paraquat resistance in hairy fleabane.

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Multiple resistance of Conyza sumatrensis to Chlorimuronethyl and to Glyphosate

Planta Daninha ◽

10.1590/s0100-83582014000200019 ◽

2014 ◽

Vol 32 (2) ◽

pp. 409-416 ◽

Cited By ~ 23

Author(s):

G. Santos ◽

R.S. Oliveira Jr. ◽

J. Constantin ◽

A. C. Francischini ◽

J. B. Osipe

Keyword(s):

Weed Control ◽

Shoot Biomass ◽

Multiple Resistance ◽

Response Curves ◽

No Till ◽

Herbicide Treatments ◽

Grain Crop ◽

Chlorimuron Ethyl ◽

Resistance To Herbicides ◽

Weed Resistance

Weed resistance to herbicides has been a major issue in Brazil, mainly due to the inefficiency of the herbicides used in no-till areas and to the high cost of these herbicide treatments. Failures in controlling the weed Conyza have been reported in Western and Northern grain crop areas in Paraná (Brazil). This work aimed to evaluate the potential occurrence of C. sumatrensis biotypes resistant to the herbicides chlorimuron-ethyl and glyphosate. Experiments were carried out under greenhouse conditions with four biotypes (Cascavel-2, Toledo-4, Tupãssi-6, and Assis Chateaubriand-7) possibly resistant to, as well as a population considered susceptible to chlorimuron-ethyl and glyphosate. To obtain dose-response curves, eight herbicide doses of chlorimuron-ethyl (0, 2.5, 5, 10, 20, 40, 80 and 160 g ha-1) and glyphosate (0, 90, 180, 360, 720, 1,440, 2,880 and 5,760 g e.a. ha-1) were applied and weed control and shoot biomass evaluations were made. Results provided evidence that two biotypes (Cascavel-2 and Tupãssi-6) were resistant to glyphosate and four biotypes (Cascavel-2, Toledo-4, Tupãssi-6 and Assis Chateaubriand-7) were resistant to chlorimuronethyl. Multiple resistance to glyphosate and chlorimuron was confirmed for biotypes Cascavel2 and Tupãssi 6. This is the first report on multiple resistance in Conyza sumatrensis, worldwide.

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Resistance and differential susceptibility of Bidens pilosa and B. subalternans biotypes to ALS-inhibiting herbicides

Scientia Agricola ◽

10.1590/s0103-90162006000200005 ◽

2006 ◽

Vol 63 (2) ◽

pp. 139-145 ◽

Cited By ~ 10

Author(s):

Ramiro Fernando López-Ovejero ◽

Saul Jorge Pinto de Carvalho ◽

Marcelo Nicolai ◽

Aluana Gonçalves Abreu ◽

Maria Tereza Grombone-Guaratini ◽

...

Keyword(s):

Differential Susceptibility ◽

Biological Characteristics ◽

Cross Resistance ◽

Fresh Weight ◽

Bidens Pilosa ◽

Resistance Patterns ◽

Chlorimuron Ethyl ◽

Agricultural Areas ◽

Chemical Groups ◽

Diverse Groups

The frequent application of herbicides in agricultural areas may select resistant biotypes in weed populations, whose biological characteristics influence the speed and patterns of resistance. This research aims to charactere, simultaneously, resistance patterns and differential susceptibility of Bidens pilosa and B. subalternans biotypes to ALS-inhibiting herbicides of the imidazolinone and sulfonylurea chemical groups. Six hairy beggarticks biotypes, four suspected resistant and two known susceptible, were treated with eight rates of chlorimuron-ethyl or imazethapyr, in greenhouse conditions. Percent control and percent fresh weight of the plants were evaluated at 28 days after the application. B. subalternans is less susceptible to ALS-inhibiting herbicides than B. pilosa; B. subalternans biotypes were more resistant than B. pilosa biotypes; there are B. pilosa and B. subalternans biotypes with cross resistance to the ALS-inhibiting herbicides of the sulfonylurea and imidazolinone groups; there are different patterns of cross resistance to the diverse groups of ALS-inhibiting herbicides.

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Confirmation of S-metolachlor resistance in Palmer amaranth (Amaranthus palmeri)

Weed Technology ◽

10.1017/wet.2019.44 ◽

2019 ◽

Vol 33 (5) ◽

pp. 720-726 ◽

Cited By ~ 4

Author(s):

Chad Brabham ◽

Jason K. Norsworthy ◽

Michael M. Houston ◽

Vijay K Varanasi ◽

Tom Barber

Keyword(s):

Dose Response ◽

Resistance Mechanism ◽

Acetolactate Synthase ◽

Chain Fatty Acid ◽

Palmer Amaranth ◽

Cross Resistance ◽

Amaranthus Palmeri ◽

Glutathione S Transferase ◽

Long Chain Fatty Acid ◽

Long Chain

AbstractS-Metolachlor is commonly used by soybean and cotton growers, especially with POST treatments for overlapping residuals, to obtain season-long control of glyphosate- and acetolactate synthase (ALS)–resistant Palmer amaranth. In Crittenden County, AR, reports of Palmer amaranth escapes following S-metolachlor treatment were first noted at field sites near Crawfordsville and Marion in 2016. Field and greenhouse experiments were conducted to confirm S-metolachlor resistance and to test for cross-resistance to other very-long-chain fatty acid (VLCFA)–inhibiting herbicides in Palmer amaranth accessions from Crawfordsville and Marion. Palmer amaranth control in the field (soil <3% organic matter) 14 d after treatment (DAT) was ≥94% with a 1× rate of acetochlor (1,472 g ai ha–1; emulsifiable concentrate formulation) and dimethenamid-P (631 g ai ha–1). However, S-metolachlor at 1,064 g ai ha–1 provided only 76% control, which was not significantly different from the 1/2× and 1/4× rates of dimethenamid-P and acetochlor (66% to 85%). In the greenhouse, Palmer amaranth accessions from Marion and Crawfordsville were 9.8 and 8.3 times more resistant to S-metolachlor compared with two susceptible accessions based on LD50 values obtained from dose–response experiments. Two-thirds and 1.5 times S-metolachlor at 1,064 g ha–1 were the estimated rates required to obtain 90% mortality of the Crawfordsville and Marion accessions, respectively. Data collected from the field and greenhouse confirm that these accessions have evolved a low level of resistance to S-metolachlor. In an agar-based assay, the level of resistance in the Marion accession was significantly reduced in the presence of a glutathione S-transferase (GST) inhibitor, suggesting that GSTs are the probable resistance mechanism. With respect to other VLCFA-inhibiting herbicides, Marion and Crawfordsville accessions were not cross-resistant to acetochlor, dimethenamid-P, or pyroxasulfone. However, both accessions, based on LD50 values obtained from greenhouse dose–response experiments, exhibited reduced sensitivity (1.5- to 3.6-fold) to the tested VLCFA-inhibiting herbicides.

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Cross-Resistance to Imazapic and Imazapyr in a Weedy Rice (Oryza sativa) Biotype Found in Malaysia

Planta Daninha ◽

10.1590/s0100-83582018360100058 ◽

2018 ◽

Vol 36 (0) ◽

Cited By ~ 3

Author(s):

M. DILIPKUMAR ◽

N.R. BURGOS ◽

T.S. CHUAH ◽

S. ISMAIL

Keyword(s):

Rice Field ◽

Rice Cultivar ◽

Management Tool ◽

Cross Resistance ◽

Weedy Rice ◽

Effective Management ◽

Herbicide Resistant ◽

First Case ◽

Direct Seeded ◽

Selection Of

ABSTRACT: The Clearfield® rice production system is an effective management tool for weedy rice and other weeds in the direct-seeded rice culture. However, if farmers cultivating the Clearfield® rice disregard stewardship recommendations, the industry could face a problem of herbicide-resistant weedy rice which would occur through the selection of outcrosses. This study aimed to confirm imidazolinone-resistant weedy rice in Malaysia. The resistant weedy rice (R-WR) was found to be 67 fold more resistant to OnDuty® (premix of imazapic and imazapyr) than the susceptible weedy rice (S-WR) based on the GR50 values (rate that causes 50% inhibition of shoot growth). The Clearfield® rice cultivar was 32-fold more tolerant to OnDuty® than the S-WR. Furthermore, the R-WR was 54 and 89 fold more resistant to imazapic and imazapyr applied separately than the S-WR, respectively. The Clearfield® rice was 140- and 40-fold more tolerant to imazapic and imazapyr, respectively than the S-WR. The R-WR biotype was susceptible to non-selective herbicides glyphosate and glufosinate, as well as the selective graminicide quizalofop. Oxadiazon controlled the R-WR biotype, but pretilachlor was ineffective. The present study documented the first case of weedy rice that was cross-resistant to imazapic and imazapyr in Malaysian Clearfield® rice field.

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Resistance mechanism for ibrutinib in marginal zone lymphoma

Blood Advances ◽

10.1182/bloodadvances.2018029058 ◽

2019 ◽

Vol 3 (4) ◽

pp. 500-502 ◽

Cited By ~ 4

Author(s):

Narendranath Epperla ◽

Arwa Y. Shana’ah ◽

Dan Jones ◽

Beth A. Christian ◽

Sabarish Ayyappan ◽

...

Keyword(s):

Marginal Zone ◽

Acquired Resistance ◽

Resistance Mechanism ◽

Marginal Zone Lymphoma ◽

First Case ◽

Molecular Events ◽

Key Points

Key Points The molecular events leading to primary and acquired resistance to ibrutinib in marginal zone lymphoma have not been studied. We describe the first case of MZL with acquired resistance to ibrutinib in which mutations in both BTK (C481S) and PLCG2 are documented.

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