Investigating the mechanism of glyphosate resistance in rigid ryegrass (Lolium ridigum)

Baerson, Scott R.; Rodriguez, Damian; Biest, N.; Tran, Minhtien; You, Jinling; Kreuger, Roger W.; Dill, Gerald M.; Pratley, James; Gruys, Kenneth J.

doi:10.1614/0043-1745(2002)050[0721:itmogr]2.0.co;2

Cited by 80 publications

(81 citation statements)

References 32 publications

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“…The authors also reported that in this type of resistance, the EPSPS enzyme remains sensitive to glyphosate; what changes is that the amount of herbicide required to reduce the activity of EPSPs increases with the number of copies of gene EPSPs. Baerson et al (2002) found evidence of gene amplification or cosegregation of the specific gene of the varying enzyme in the resistant biotype of Lolium multiflorum.…”

Section: Resultsmentioning

confidence: 94%

Effect of glyphosate on the physiological parameters of horseweed

Santos

Várgas

Christoffoleti

et al. 2014

Agraria

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The aim of this study was to determine changes in the photosynthetic process and the inhibition of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPs) by shikimic acid accumulation, after application of the herbicide glyphosate in four biotypes of C. sumatrensis collected in the state of Rio Grande do Sul. Therefore, the experiments were conducted under greenhouse and laboratory, assessing plant biomass, photosynthesis rate, transpiration and water use efficiency; the amount of shikimic acid was calculated for each treatment. Glyphosate application reduced growth and affected the photosynthesis rate and water use efficiency of the biotypes differentially, and the resistant biotype had small interference from glyphosate, while physiological parameters of the susceptible biotype were deeply affected by the herbicide. Susceptible biotypes had higher shikimic acid accumulation than the resistant biotype, indicating differential sensitivity of EPSPs to glyphosate between resistant and sensitive biotypes. Key words: Conyza sumatrensis, EPSPs, resistance, shikimic acidEfeito do glyphosate sobre parâmetros fisiológicos de buva RESUMO O objetivo do trabalho foi determinar alterações no processo fotossintético e na inibição da 5-enolpiruvilchiquimato-3-fosfato sintase (EPSPs), por meio do acúmulo de ácido chiquímico, após a aplicação do herbicida glyphosate, em quatro biótipos de C. sumatrensis coletados no Estado do Rio Grande do Sul. Para isto foram conduzidos experimentos em casa-de-vegetação e em laboratório avaliando fitomassa seca da parte aérea, taxa de fotossíntese, transpiração e eficiência do uso da água; a quantidade de ácido chiquímico foi calculada para cada tratamento. A aplicação do glyphosate reduziu o crescimento e afetou a taxa de fotossíntese a eficiência do uso da água dos biótipos de forma diferencial, sendo que o biótipo resistente teve pequena interferência do glyphosate enquanto os parâmetros fisiológicos do biótipo suscetível foram profundamente afetados pelo herbicida. Nos biótipos suscetíveis o acúmulo de ácido chiquímico foi maior que no biótipo resistente evidenciando sensibilidade diferencial da EPSPs dos biótipos resistente e sensíveis ao glyphosate. Palavras

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Section: Resultsmentioning

confidence: 94%

Effect of glyphosate on the physiological parameters of horseweed

Santos

Várgas

Christoffoleti

et al. 2014

Agraria

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“…There is evidence for enhanced EPSPS expression in glyphosate-resistant weeds, but no previous evidence for EPSPS gene amplification. Two-to threefold elevated EPSPS expression and enzyme activity were found in glyphosate-resistant L. rigidum, and EPSPS from glyphosate-resistant and -susceptible plants were equally sensitive to glyphosate (31). However, the elevated expression was not due to gene amplification because EPSPS gene copy number in L. rigidum was examined using DNA blot hybridizations and glyphosate-resistant lines did not have increased EPSPS gene copy number in comparison with glyphosate-susceptible lines.…”

Section: Discussionmentioning

confidence: 96%

Gene amplification confers glyphosate resistance in Amaranthus palmeri

Gaines

Zhang

Wang

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

603

868

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The herbicide glyphosate became widely used in the United States and other parts of the world after the commercialization of glyphosate-resistant crops. These crops have constitutive overexpression of a glyphosate-insensitive form of the herbicide target site gene, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Increased use of glyphosate over multiple years imposes selective genetic pressure on weed populations. We investigated recently discovered glyphosate-resistant Amaranthus palmeri populations from Georgia, in comparison with normally sensitive populations. EPSPS enzyme activity from resistant and susceptible plants was equally inhibited by glyphosate, which led us to use quantitative PCR to measure relative copy numbers of the EPSPS gene. Genomes of resistant plants contained from 5-fold to more than 160-fold more copies of the EPSPS gene than did genomes of susceptible plants. Quantitative RT-PCR on cDNA revealed that EPSPS expression was positively correlated with genomic EPSPS relative copy number. Immunoblot analyses showed that increased EPSPS protein level also correlated with EPSPS genomic copy number. EPSPS gene amplification was heritable, correlated with resistance in pseudo-F 2 populations, and is proposed to be the molecular basis of glyphosate resistance. FISH revealed that EPSPS genes were present on every chromosome and, therefore, gene amplification was likely not caused by unequal chromosome crossing over. This occurrence of gene amplification as an herbicide resistance mechanism in a naturally occurring weed population is particularly significant because it could threaten the sustainable use of glyphosate-resistant crop technology.5-enolpyruvylshikimate-3-phosphate synthase | herbicide resistance | mobile genetic element | evolution | Palmer amaranth

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“…Previous reports have shown that the substitution of proline to serine, leucine, or threonine resulted in more glyphosate resistance in L. rigidum and L. multiflorum (Baerson et al, 2002a;Perez-Jones et al, 2007). Similarly, the presence of two EPSPS loci in susceptible A. palmeri was observed, with one being amplified in glyphosate-resistant plants (Gaines et al, 2013).…”

Section: Epsps Alleles and Amino Acid Substitutions In D Insularis Rmentioning

confidence: 71%

EPSPS variability, gene expression, and enzymatic activity in glyphosate-resistant biotypes of Digitaria insularis

Galeano¹,

Barroso²,

Vasconcelos³

et al. 2016

Genet. Mol. Res.

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ABSTRACT. Weed resistance to herbicides is a natural phenomenon that exerts selection on individuals in a population. In Brazil, glyphosate resistance was recently detected in Digitaria insularis. The objective of this study was to elucidate mechanisms of weed resistance in this plant, including genetic variability, allelism, amino acid substitutions, gene expression, and enzymatic activity levels. Most of these have not previously been studied in this species. D. insularis DNA sequences were used to analyze genetic variability. cDNA from resistant and susceptible plants was used to identify 2 E. Galeano et al. Genetics and Molecular Research 15 (3): gmr.15038730 mutations, alleles, and 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) expression, using real-time quantitative reverse transcriptionpolymerase chain reaction. In addition, EPSPS activity was measured. We found a decrease in genetic variability between populations related to glyphosate application. Substitutions from proline to threonine and tyrosine to cysteine led to a decrease in EPSPS affinity for the glyphosate. In addition, the EPSPS enzymatic activity was slightly higher in resistant plants, whereas EPSPS gene expression was almost identical in both biotypes, suggesting feedback regulation at different levels. To conclude, our results suggest new molecular mechanisms used by D. insularis to increase glyphosate resistance.

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Investigating the mechanism of glyphosate resistance in rigid ryegrass (Lolium ridigum)

Cited by 80 publications

References 32 publications

Effect of glyphosate on the physiological parameters of horseweed

Effect of glyphosate on the physiological parameters of horseweed

Gene amplification confers glyphosate resistance in Amaranthus palmeri

EPSPS variability, gene expression, and enzymatic activity in glyphosate-resistant biotypes of Digitaria insularis

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