EPSPS Gene Amplification is Present in the Majority of Glyphosate-Resistant Illinois Waterhemp (Amaranthus tuberculatus) Populations

With the frequency of glyphosate-resistant waterhemp increasing throughout the Midwest, the identification of resistant populations has become important for managing this species. However, high-throughput screening for glyphosate resistance in the greenhouse is tedious and inefficient. Research was conducted to document the occurrence of glyphosate-resistant waterhemp throughout the state of Illinois, and to determine whether a molecular assay for 5-enolypyruvyl-shikimate-3-phosphate synthase (EPSPS) gene amplification can be used as an alternative means to detect resistant populations. Populations throughout the state of Illinois were collected in 2010 and screened for glyphosate resistance using a whole-plant assay in a greenhouse, and survivors were examined for EPSPS gene amplification. Of 80 populations investigated, 22 were glyphosate resistant based on the greenhouse screen, and gene amplification was identified in 20 (91%) of the resistant populations. Although there are multiple mechanisms for glyphosate resistance in waterhemp, a molecular test for EPSPS gene amplification provides a rapid alternative for identification of glyphosate resistance in most populations.

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A Multistate Study of the Association Between Glyphosate Resistance and EPSPS Gene Amplification in Waterhemp (Amaranthus tuberculatus)

Weed Science ◽

10.1614/ws-d-14-00149.1 ◽

2015 ◽

Vol 63 (3) ◽

pp. 569-577 ◽

Cited By ~ 31

Author(s):

Laura A. Chatham ◽

Kevin W. Bradley ◽

Greg R. Kruger ◽

James R. Martin ◽

Micheal D. K. Owen ◽

...

Keyword(s):

Gene Amplification ◽

Copy Number ◽

Quantitative Relationship ◽

Glyphosate Resistance ◽

Epsps Gene ◽

Number Magnitude ◽

Site Of Action ◽

Amaranthus Tuberculatus ◽

Polymerase Chain ◽

The Relationship

Waterhemp is an increasingly problematic weed in the U.S. Midwest, having now evolved resistances to herbicides from six different site-of-action groups. Glyphosate-resistant waterhemp in the Midwest is especially concerning given the economic importance of glyphosate in corn and soybean production. Amplification of the target-site gene, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) was found to be the mechanism of glyphosate resistance in Palmer amaranth, a species closely related to waterhemp. Here, the relationship between glyphosate resistance and EPSPS gene amplification in waterhemp was investigated. Glyphosate dose response studies were performed at field sites with glyphosate-resistant waterhemp in Illinois, Kansas, Kentucky, Missouri, and Nebraska, and relative EPSPS copy number of survivors was determined via quantitative real-time polymerase chain reaction (qPCR). Waterhemp control increased with increasing glyphosate rate at all locations, but no population was completely controlled even at the highest rate (3,360 g ae ha−1). EPSPS gene amplification was present in plants from four of five locations (Illinois, Kansas, Missouri, and Nebraska) and the proportion of plants with elevated copy number was generally higher in survivors from glyphosate-treated plots than in plants from the untreated control plots. Copy number magnitude varied by site, but an overall trend of increasing copy number with increasing rate was observed in populations with gene amplification, suggesting that waterhemp plants with more EPSPS copies are more resistant. Survivors from the Kentucky population did not have elevated EPSPS copy number. Instead, resistance in this population was attributed to the EPSPS Pro106Ser mutation. Results herein show a quantitative relationship between glyphosate resistance and EPSPS gene amplification in some waterhemp populations, while highlighting that other mechanisms also confer glyphosate resistance in waterhemp.

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Fitness Cost Associated With Enhanced EPSPS Gene Copy Number and Glyphosate Resistance in an Amaranthus tuberculatus Population

Frontiers in Plant Science ◽

10.3389/fpls.2021.651381 ◽

2021 ◽

Vol 12 ◽

Author(s):

Helen M. Cockerton ◽

Shiv S. Kaundun ◽

Lieselot Nguyen ◽

Sarah Jane Hutchings ◽

Richard P. Dale ◽

...

Keyword(s):

Interspecific Competition ◽

Gene Amplification ◽

Copy Number ◽

Gene Copy Number ◽

Glyphosate Resistance ◽

Gene Copy ◽

Competitive Response ◽

Trade Off ◽

Epsps Gene ◽

Amaranthus Tuberculatus

The evolution of resistance to pesticides in agricultural systems provides an opportunity to study the fitness costs and benefits of novel adaptive traits. Here, we studied a population of Amaranthus tuberculatus (common waterhemp), which has evolved resistance to glyphosate. The growth and fitness of seed families with contrasting levels of glyphosate resistance was assessed in the absence of glyphosate to determine their ability to compete for resources under intra- and interspecific competition. We identified a positive correlation between the level of glyphosate resistance and gene copy number for the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) glyphosate target, thus identifying gene amplification as the mechanism of resistance within the population. Resistant A. tuberculatus plants were found to have a lower competitive response when compared to the susceptible phenotypes with 2.76 glyphosate resistant plants being required to have an equal competitive effect as a single susceptible plant. A growth trade-off was associated with the gene amplification mechanism under intra-phenotypic competition where 20 extra gene copies were associated with a 26.5 % reduction in dry biomass. Interestingly, this growth trade-off was mitigated when assessed under interspecific competition from maize.

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No fitness cost of glyphosate resistance endowed by massive EPSPS gene amplification in Amaranthus palmeri

Planta ◽

10.1007/s00425-013-2022-x ◽

2014 ◽

Vol 239 (4) ◽

pp. 793-801 ◽

Cited By ~ 64

Author(s):

Martin M. Vila-Aiub ◽

Sou S. Goh ◽

Todd A. Gaines ◽

Heping Han ◽

Roberto Busi ◽

...

Keyword(s):

Gene Amplification ◽

Glyphosate Resistance ◽

Fitness Cost ◽

Amaranthus Palmeri ◽

Epsps Gene

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EPSPS Gene Copy Number and Whole-Plant Glyphosate Resistance Level in Kochia scoparia

PLoS ONE ◽

10.1371/journal.pone.0168295 ◽

2016 ◽

Vol 11 (12) ◽

pp. e0168295 ◽

Cited By ~ 18

Author(s):

Todd A. Gaines ◽

Abigail L. Barker ◽

Eric L. Patterson ◽

Philip Westra ◽

Eric P. Westra ◽

...

Keyword(s):

Copy Number ◽

Gene Copy Number ◽

Glyphosate Resistance ◽

Gene Copy ◽

Kochia Scoparia ◽

Resistance Level ◽

Epsps Gene ◽

Whole Plant

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A Simple In-Season Bioassay for Detecting Glyphosate Resistance in Grass and Broadleaf Weeds Prior to Herbicide Application in the Field

Weed Science ◽

10.1614/ws-d-14-00046.1 ◽

2014 ◽

Vol 62 (4) ◽

pp. 597-607 ◽

Cited By ~ 4

Author(s):

Shiv S. Kaundun ◽

Sarah-Jane Hutchings ◽

Suzanne C. Harris ◽

Lucy V. Jackson ◽

Rekha Shashi-Kiran ◽

...

Keyword(s):

Resistance Management ◽

Informed Choice ◽

Cost Effective ◽

Glyphosate Resistance ◽

Resistance Mechanisms ◽

Field Application ◽

Current Season ◽

Epsps Gene ◽

Percentage Survival ◽

Whole Plant

The implementation of a successful glyphosate resistance management strategy requires a simple and cost-effective method for detecting resistance in key weeds. To date, however, glyphosate resistance is still routinely confirmed via laborious and time consuming whole-plant pot assays using seeds collected at the end of the growing season. Here, we describe a simple, early-season bioassay for detecting evolved glyphosate resistance in grass and broadleaf weeds. It involves transplanting suspected glyphosate resistant seedlings alongside known sensitive and resistant standards into agar containing informative rates of herbicide and recording percentage survival 14 d after plating. The method was validated using sensitive and resistant populations of Lolium, Eleusine, Conyza, and Amaranthus species encompassing the main glyphosate resistance mechanisms, namely, impaired translocation, EPSPS gene duplication, and mutations. The whole plant pot and agar-based seedling tests generated comparable resistance indices in dose-response assays and percentage survival at discriminating glyphosate rates. The method was applied successfully to detect resistance in a rigid ryegrass population collected from a French vineyard well before glyphosate was applied in the field for the current season. Additionally, the test was shown to be highly transferable to several other grass and broadleaf weeds that have evolved resistance to glyphosate. One major attribute of the method is that it is capable of detecting resistance regardless of the mechanism involved. In addition to being very simple, quick and, cost-effective, it allows determination of glyphosate resistance in weeds prior to field application. It thus offers the opportunity for an informed choice of herbicides for effective weed control.

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Glyphosate-Resistant Palmer Amaranth (Amaranthus palmeri) in Nebraska: Confirmation, EPSPS Gene Amplification, and Response to POST Corn and Soybean Herbicides

Weed Technology ◽

10.1614/wt-d-16-00109.1 ◽

2017 ◽

Vol 31 (1) ◽

pp. 80-93 ◽

Cited By ~ 29

Author(s):

Parminder S. Chahal ◽

Vijay K. Varanasi ◽

Mithila Jugulam ◽

Amit J. Jhala

Keyword(s):

Gene Amplification ◽

Crop Production ◽

Acetolactate Synthase ◽

The United States ◽

Palmer Amaranth ◽

Amaranthus Palmeri ◽

Epsps Gene ◽

South Central ◽

Whole Plant ◽

Herbicide Programs

Palmer amaranth is the most problematic weed in agronomic crop production fields in the United States. A Palmer amaranth biotype was not controlled with sequential applications of glyphosate in glyphosate-resistant (GR) soybean production field in south-central Nebraska. The seeds of the putative GR Palmer amaranth biotype were collected in the fall of 2015. The objectives of this study were to (1) confirm GR Palmer amaranth and determine the level of resistance in a whole-plant dose-response bioassay, (2) determine the copy number of 5-enolpyruvylshikimate-3-phosphate (EPSPS) gene, the molecular target of glyphosate, and (3) evaluate the response of GR Palmer amaranth biotype to POST corn and soybean herbicides with different modes-of-action. Based on the effective dose required to control 90% of plants (ED90), the putative GR Palmer amaranth biotype was 37- to 40-fold resistant to glyphosate depending on the glyphosate-susceptible (GS) used as a baseline population.EPSPSgene amplification was present in the GR Palmer amaranth biotype with up to 32 to 105 EPSPS copies compared to the known GS biotypes. Response of GR Palmer amaranth to POST corn and soybean herbicides suggest reduced sensitivity to atrazine, hydroxyphenylpyruvate dioxygenase (HPPD)- (mesotrione, tembotrione, and topramezone), acetolactate synthase (ALS)- (halosulfuron-methyl), and protoporphyrinogen oxidase (PPO)- (carfentrazone and lactofen) inhibitors. GR Palmer amaranth was effectively controlled (>90%) with glufosinate applied at 593 g ai ha−1with ≥95% reduction in biomass. More research is needed to determine whether this biotype exhibits multiple resistant to other group of herbicides and evaluate herbicide programs for effective management in corn and soybean.

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The Right to Education in India

10.1093/oso/9780199494286.001.0001 ◽

2019 ◽

Author(s):

Florian Matthey-Prakash

Keyword(s):

Private Education ◽

The State ◽

Legal Empowerment ◽

Right To Education ◽

The Poor ◽

Potential System ◽

Education In India ◽

Alternative Means ◽

Education Act ◽

The Right

What does it mean for education to be a fundamental right, and how may children benefit from it? Surprisingly, even when the right to education was added to the Indian Constitution as Article 21A, this question received barely any attention. This book identifies justiciability (or, more broadly, enforceability) as the most important feature of Article 21A, meaning that children and their parents must be provided with means to effectively claim their right from the state. Otherwise, it would remain a ‘right’ only on paper. The book highlights how lack of access to the Indian judiciary means that the constitutional promise of justiciability is unfulfilled, particularly so because the poor, who cannot afford quality private education for their children, must be the main beneficiaries of the right. It then deals with possible alternative means the state may provide for the poor to claim the benefits under Article 21A, and identifies the grievance redress mechanism created by the Right to Education Act as a potential system of enforcement. Even though this system is found to be deficient, the book concludes with an optimistic outlook, hoping that rights advocates may, in the future, focus on improving such mechanisms for legal empowerment.

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A double EPSPS gene mutation endowing glyphosate resistance shows a remarkably high resistance cost

Plant Cell & Environment ◽

10.1111/pce.13067 ◽

2017 ◽

Vol 40 (12) ◽

pp. 3031-3042 ◽

Cited By ~ 24

Author(s):

Heping Han ◽

Martin M. Vila-Aiub ◽

Adam Jalaludin ◽

Qin Yu ◽

Stephen B. Powles

Keyword(s):

Gene Mutation ◽

High Resistance ◽

Glyphosate Resistance ◽

Epsps Gene ◽

Resistance Cost

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Why and How to Make Plant Conservation Ecosystem-Based

Sustainable Agriculture Research ◽

10.5539/sar.v1n1p48 ◽

2012 ◽

Vol 1 (1) ◽

pp. 48 ◽

Cited By ~ 4

Author(s):

Alan Hamilton ◽

Shengji Pei ◽

Huyin Huai ◽

Seona Anderson

Keyword(s):

Information Systems ◽

Ecosystem Services ◽

Plant Species ◽

Plant Cover ◽

Plant Conservation ◽

The State ◽

The Earth ◽

Whole Plant ◽

Training Programmes ◽

Ecologically Sustainable

Compared to other groups of organisms, plants require distinctive approaches in their conservation because of their keystone roles in ecosystems and economies. The state of the whole plant cover of the Earth should be of concern to conservationists – for its capacity to ensure the survival of plant species, deliver ecosystem services (locally to globally) and provide produce from plants in ecologically sustainable ways. The primary targets of attention in ecosystem-based plant conservation are the relationships between people and plants, as relevant to every locality, rather than the species-centric approach of conventional plant conservation. Moving plant conservation to an ecosystem-based approach will require the development of training programmes for field practitioners and of information systems for their use.

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A Comparative Institutional Approach to Law and Legal Institutions

Victoria University of Wellington Law Review ◽

10.26686/vuwlr.v26i1.6181 ◽

1996 ◽

Vol 26 (1) ◽

pp. 109

Author(s):

George Barker

Keyword(s):

The State ◽

Social Goals ◽

Key Factors ◽

Institutional Approach ◽

Law And Policy ◽

Role Of The State ◽

Institutional Structures ◽

Alternative Means ◽

Made In

The late 1980s and early 1990s saw a revolution in economic policy and a transformation of the New Zealand economy. Such events also involved a revolution in legal thought and analysis. This article brings the main elements of this new economic approach to law and policy to a wider audience. It seeks to review the main features of the recent and significant advances that have been made in the economic analysis of organisations and institutions. The article first discusses the fundamental factors which must be recognised as constraints on the ability to secure an ideal society. It then discusses how private arrangements seek to overcome these constraints and the limits to their success. The role of the state in alleviating or overcoming problems with private solutions is also discussed, with the author stressing the need to recognise that the state is not an omniscient and omnipotent solver of social problems. The author concludes that the analysis of government and government policy needs to be based on a comparative institutional approach involving an assessment of institutional structures according to the processes and outcomes they involve, utilising generally accepted criteria for making social choices. Key factors that must be considered in comparing alternative means for achieving social goals are identified.

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