Genetic diversity and in silico evidence of target-site mutation in the EPSPS gene in endowing glyphosate resistance in Eleusine indica (L.) from Malaysia

Due to the overdependence on glyphosate to manage weeds in fallow conditions, glyphosate resistance has developed in various biotypes of several grass weeds, including Chloris virgata Sw. The first case of glyphosate resistance in C. virgata was found in 2015 in Australia, and since then several cases have been confirmed in several biotypes across Australia. Pot studies were conducted with 10 biotypes of C. virgata to determine glyphosate resistance levels. The biotypes were identified as either susceptible, moderately resistant or highly resistant based on the glyphosate dose required to kill 50% of plants. Two glyphosate-susceptible (GS) and two glyphosate-resistant (GR) biotypes were identified by the dose-response study and analyzed for the presence of target-site mutation in the 5–enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene. Performance of alternative herbicides to glyphosate as well as the double-knock herbicide approach was evaluated on the two GS (Ch and SGM2) and two GR (SGW2 and CP2) biotypes. Three herbicides, clethodim, haloxyfop and paraquat, were found to be effective (100% control) against all four biotypes when applied at the 4–5 leaf stage. All the sequential herbicide treatments, such as glyphosate followed by paraquat and glufosinate-ammonium followed by paraquat, provided 100% control of all four biotypes of C. virgata. This study identified effective herbicide options for the control of GR C. virgata and showed that target-site mutations were involved in the resistance of two biotypes to glyphosate (SGW2 and CP2). Results could aid farmers in selecting herbicides to manage C. virgata in their fields.

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Resistance to ACCase inhibitors in Eleusine indica from Brazil involves a target site mutation

Planta Daninha ◽

10.1590/s0100-83582012000300025 ◽

2012 ◽

Vol 30 (3) ◽

pp. 675-681 ◽

Cited By ~ 11

Author(s):

M.D. Osuna ◽

I.C.G.R. Goulart ◽

R.A. Vidal ◽

A. Kalsing ◽

J.P. Ruiz Santaella ◽

...

Keyword(s):

Amino Acid Position ◽

Target Site ◽

In Vitro Assays ◽

Site Mutation ◽

Eleusine Indica ◽

Herbicide Resistant ◽

Frequent Use ◽

Target Site Resistance ◽

Grass Weed

Eleusine indica (goosegrass) is a diploid grass weed which has developed resistance to ACCase inhibitors during the last ten years due to the intensive and frequent use of sethoxydim to control grass weeds in soybean crops in Brazil. Plant dose-response assays confirmed the resistant behaviour of one biotype obtaining high resistance factor values: 143 (fenoxaprop), 126 (haloxyfop), 84 (sethoxydim) to 58 (fluazifop). ACCase in vitro assays indicated a target site resistance as the main cause of reduced susceptibility to ACCase inhibitors. PCR-generated fragments of the ACCase CT domain of the resistant and sensitive reference biotype were sequenced and compared. A point mutation was detected within the triplet of aspartate at the amino acid position 2078 (referred to EMBL accession no. AJ310767) and resulted in the triplet of glycine. These results constitute the first report on a target site mutation for a Brazilian herbicide resistant grass weed.

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Evolution of Target-Site Resistance to Glyphosate in an Amaranthus palmeri Population from Argentina and Its Expression at Different Plant Growth Temperatures

Plants ◽

10.3390/plants8110512 ◽

2019 ◽

Vol 8 (11) ◽

pp. 512 ◽

Cited By ~ 4

Author(s):

Kaundun ◽

Jackson ◽

Hutchings ◽

Galloway ◽

Marchegiani ◽

...

Keyword(s):

Fold Increase ◽

Glyphosate Resistance ◽

Target Site ◽

Amaranthus Palmeri ◽

Site Mutation ◽

Medium Temperature ◽

Soybean Field ◽

Over Expression ◽

Target Site Resistance ◽

The Difference

The mechanism and expression of resistance to glyphosate at different plant growing temperatures was investigated in an Amaranthus palmeri population (VM1) from a soybean field in Vicuña Mackenna, Cordoba, Argentina. Resistance was not due to reduced glyphosate translocation to the meristem or to EPSPS duplication, as reported for most US samples. In contrast, a proline 106 to serine target-site mutation acting additively with EPSPS over-expression (1.8-fold increase) was respectively a major and minor contributor to glyphosate resistance in VM1. Resistance indices based on LD50 values generated using progenies from a cross between 52 PS106 VM1 individuals were estimated at 7.1 for homozygous SS106 and 4.3 for heterozygous PS106 compared with homozygous wild PP106 plants grown at a medium temperature of 24 °C day/18 °C night. A larger proportion of wild and mutant progenies survived a single commonly employed glyphosate rate when maintained at 30 °C day/26 °C night compared with 20 °C day/16 night in a subsequent experiment. Interestingly, the P106S mutation was not identified in any of the 920 plants analysed from 115 US populations, thereby potentially reflecting the difference in A. palmeri control practices in Argentina and USA.

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Rigid Ryegrass (Lolium rigidum) Populations Containing a Target Site Mutation in EPSPS and Reduced Glyphosate Translocation Are More Resistant to Glyphosate

Weed Science ◽

10.1614/ws-d-11-00154.1 ◽

2012 ◽

Vol 60 (3) ◽

pp. 474-479 ◽

Cited By ~ 31

Author(s):

Yazid Bostamam ◽

Jenna M. Malone ◽

Fleur C. Dolman ◽

Peter Boutsalis ◽

Christopher Preston

Keyword(s):

Weed Control ◽

Glyphosate Resistance ◽

Resistance Mechanisms ◽

Target Site ◽

Lolium Rigidum ◽

Site Mutation ◽

Susceptible Population ◽

Intensive Use ◽

Rigid Ryegrass ◽

Two Populations

Glyphosate is widely used for weed control in the grape growing industry in southern Australia. The intensive use of glyphosate in this industry has resulted in the evolution of glyphosate resistance in rigid ryegrass. Two populations of rigid ryegrass from vineyards, SLR80 and SLR88, had 6- to 11-fold resistance to glyphosate in dose-response studies. These resistance levels were higher than two previously well-characterized glyphosate-resistant populations of rigid ryegrass (SLR77 and NLR70), containing a modified target site or reduced translocation, respectively. Populations SLR80 and SLR88 accumulated less glyphosate, 12 and 17% of absorbed glyphosate, in the shoot in the resistant populations compared with 26% in the susceptible population. In addition, a mutation within the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) where Pro106had been substituted by either serine or threonine was identified. These two populations are more highly resistant to glyphosate as a consequence of expressing two different resistance mechanisms concurrently.

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Resistance to Glyphosate in Junglerice (Echinochloa colona) from California

Weed Science ◽

10.1614/ws-d-12-00073.1 ◽

2013 ◽

Vol 61 (1) ◽

pp. 48-54 ◽

Cited By ~ 43

Author(s):

Rocío Alarcón-Reverte ◽

Alejandro García ◽

Jaime Urzúa ◽

Albert J. Fischer

Keyword(s):

Glyphosate Resistance ◽

Population Based ◽

Target Site ◽

Northern California ◽

Site Mutation ◽

Partial Sequencing ◽

Leaf Discs ◽

Corn Field ◽

First Case ◽

Standard Population

A suspected glyphosate-resistant (R) junglerice population was collected from a glyphosate-R corn field near Durham in northern California where glyphosate had been applied at least twice a year for over 6 yr. Based on the amount of glyphosate required to reduce growth by 50% (ED50), the R population was 6.6 times more R than the susceptible (S) standard population. Based on the glyphosate concentration that inhibits EPSPS by 50% based on shikimate accumulation (I50) in leaf discs, R plants were four times more R than S plants. By 3 d after treatment with 0.42 kg ae ha−1glyphosate, the S population had accumulated approximately five times more shikimate than the R population. No differences in [14C]-glyphosate uptake and translocation were detected between R and S plants. However, partial sequencing of theEPSPSgene revealed a mutation in R plants causing a proline to serine change at EPSPS position 106 (P106S). Our results reveal the first case of a P106S target site mutation associated with glyphosate resistance in junglerice.

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Herbicide resistant weeds: the case of resistance to glyphosate

Vietnam Journal of Science Technology and Engineering ◽

10.31276/vjste.63(2).74-80 ◽

2021 ◽

Vol 63 (2) ◽

pp. 74-80

Author(s):

The Duc Ngo ◽

Keyword(s):

Weed Management ◽

Glyphosate Resistance ◽

Resistance Mechanisms ◽

Management Program ◽

Ambrosia Artemisiifolia ◽

Target Site ◽

Integrated Weed Management ◽

Weed Species ◽

Site Mutation ◽

Sites Of Action

Glyphosate has become the most widely used herbicide worldwide since 1974 with a global use of 8.6 billion kg (glyphosate active ingredient) between 1974 and 2014. This study reports on glyphosate resistant (GR) weeds and their resistance mechanisms based on global scientifically reported cases. Forty-nine different weed species have evolved resistance to glyphosate in 29 countries with a total of 318 identified cases worldwide. Fifty percent of these resistance cases were found in glyphosate-resistant cropping systems. There were 255 identified cases (80.2%) of glyphosate resistance in the top five countries (in terms of number of cases and species), namely USA, Australia, Argentina, Brazil, and Canada. The five most popular weed species (in terms of number of cases) found to be resistant to glyphosate were Conyza canadensis, Amaranthus palmeri, Amaranthus tuberculatus, Lolium perenne ssp. Multiflorum,and Ambrosia artemisiifolia with 42, 42, 29, 26, and 21 reported cases, respectively. Out of 49 weed species, 19 GR weed species were found to not only be resistant to glyphosate but also to other herbicide sites of action (multiple herbicide resistance). Glyphosate resistance mechanisms in weeds include (1) target-site alterations: target-site mutation and target-site gene amplification; and (2) non-target-site mechanisms involving different modes of exclusion from the target site: reduced glyphosate uptake, reduced glyphosate translocation, and enhanced glyphosate metabolism. It is essential to have an integrated weed management program that includes not only smart herbicide mixtures and rotations, but also cultural, manual, mechanical, and crop-based weed management methods.

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A Modified phosphate-carrier protein theory is proposed as a non-target site mechanism For glyphosate resistance in weeds

Planta Daninha ◽

10.1590/s0100-83582010000500025 ◽

2010 ◽

Vol 28 (spe) ◽

pp. 1175-1185 ◽

Cited By ~ 11

Author(s):

A.C. Roso ◽

R.A. Vidal

Keyword(s):

Control Measure ◽

Shikimate Pathway ◽

Aromatic Amino Acids ◽

Glyphosate Resistance ◽

Resistance Mechanisms ◽

Target Site ◽

Weed Species ◽

Resistance Level ◽

Epsps Gene ◽

Limited Degree

Glyphosate is an herbicide that inhibits the enzyme 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPs) (EC 2.5.1.19). EPSPs is the sixth enzyme of the shikimate pathway, by which plants synthesize the aromatic amino acids phenylalanine, tyrosine, and tryptophan and many compounds used in secondary metabolism pathways. About fifteen years ago it was hypothesized that it was unlikely weeds would evolve resistance to this herbicide because of the limited degree of glyphosate metabolism observed in plants, the low resistance level attained to EPSPs gene overexpression, and because of the lower fitness in plants with an altered EPSPs enzyme. However, today 20 weed species have been described with glyphosate resistant biotypes that are found in all five continents of the world and exploit several different resistant mechanisms. The survival and adaptation of these glyphosate resistant weeds are related toresistance mechanisms that occur in plants selected through the intense selection pressure from repeated and exclusive use of glyphosate as the only control measure. In this paper the physiological, biochemical, and genetic basis of glyphosate resistance mechanisms in weed species are reviewed and a novel and innovative theory that integrates all the mechanisms of non-target site glyphosate resistance in plants is presented.

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The First Report of Target-Site Resistance to Glyphosate in Sweet Summer Grass (Moorochloa eruciformis)

Plants ◽

10.3390/plants10091885 ◽

2021 ◽

Vol 10 (9) ◽

pp. 1885

Author(s):

Romesh Salgotra ◽

Bhagirath Singh Chauhan

Keyword(s):

Amino Acid ◽

Management Strategies ◽

Glyphosate Resistance ◽

Target Site ◽

Single Amino Acid ◽

Invasive Weeds ◽

Epsps Gene ◽

Target Site Resistance ◽

Multiple Amino Acid ◽

First Time

Sweet summer grass is a problematic weed in the central Queensland region of Australia. This study found glyphosate resistance in two biotypes (R1 and R2) of sweet summer grass. The level of resistance in these biotypes was greater than 8-fold. The glyphosate dose required to reduce dry matter by 50% (GR50) for the resistant populations varied from 1993 to 2100 g ha−1. A novel glyphosate resistance double point mutation in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene was identified for the first time in sweet summer grass. Multiple mutations, including multiple amino acid changes at the glyphosate target site, as well as mutations involving two nucleotide changes at a single amino acid codon, were observed. Both resistant biotypes exhibited a nucleotide change of CAA to ACA in codon 106, which predicts an amino acid change of proline to a threonine (Pro-106-Thr). In addition, the R1 biotype also possessed a mutation at codon 100, where a nucleotide substitution of T for G occurred (GCT to TCT), resulting in a substitution of serine for alanine (Ala-100-Ser). Understanding the molecular mechanism of glyphosate resistance will help to design effective management strategies to control invasive weeds.

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