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

PLoS ONE ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. e0168295 ◽  
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

scholarly journals Prediction of glyphosate resistance level based on EPSPS gene copy number in Kochia scoparia

2016 ◽  
Author(s):  
Todd A. Gaines ◽  
Abigail L. Barker ◽  
Eric L. Patterson ◽  
Philip Westra ◽  
Eric P. Westra ◽  
...  
Keyword(s):  
Gene Duplication ◽  
Empirical Model ◽  
Copy Number ◽  
Gene Copy Number ◽  
Glyphosate Resistance ◽  
Gene Copy ◽  
Kochia Scoparia ◽  
Resistance Level ◽  
Epsps Gene ◽  
Fallow Systems

AbstractGlyphosate-resistant (GR) Kochia scoparia has evolved in dryland chemical fallow systems throughout North America and the mechanism involves 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene duplication. Sugarbeet fields in four states were surveyed for K. scoparia in 2013 and tested for glyphosate-resistance level and EPSPS gene copy number. Glyphosate resistance was confirmed in K. scoparia populations collected from sugarbeet fields in Colorado, Wyoming, and Nebraska. The GR samples all had increased EPSPS gene copy number, with median population values up to 11. An empirical model was developed to estimate the level of glyphosate-resistance in K. scoparia based on EPSPS gene copy number. The results suggested that glyphosate susceptibility can be accurately diagnosed using EPSPS gene copy number, and further increases in EPSPS gene copy number could increase resistance levels up to 8-fold relative to susceptible K. scoparia. These trends suggest that continued glyphosate selection pressure is selecting for higher EPSPS copy number and higher resistance levels in K. scoparia. By including multiple K. scoparia samples lacking EPSPS gene duplication, our empirical model provides a more realistic estimate of fold-resistance due to EPSPS gene copy number compared to methods that do not account for normal variation of herbicide response in susceptible biotypes.

Confirmation of Glyphosate-Resistant Kochia (Kochia scoparia) from Sugar Beet Fields in Idaho and Oregon

2017 ◽  
Vol 32 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Vipan Kumar ◽  
Joel Felix ◽  
Don Morishita ◽  
Prashant Jha
Keyword(s):  
Sugar Beet ◽  
Copy Number ◽  
Cropping Systems ◽  
Gene Copy Number ◽  
Glyphosate Resistance ◽  
Gene Copy ◽  
Resistance Level ◽  
Control Programs ◽  
Gene Copies

AbstractGlyphosate-resistant (GR) kochia is an increasing management concern in major cropping systems of the northwestern US. In 2014, we investigated four putative GR kochia accessions (designated as ALA, VAL, WIL, DB) collected from sugar beet fields in eastern Oregon and southwestern Idaho to characterize the level of evolved glyphosate resistance and determine the relationship between the 5-enol-pyruvylshikimate-3-phospate synthase (EPSPS) gene copy number and level of glyphosate resistance. TheEPSPSgene copy number was used as a molecular marker to detect GR kochia in subsequent surveys in 2015 and 2016. Based on LD50values from a whole-plant dose-response study, the four putative GR kochia populations were 2.0- to 9.6-fold more resistant to glyphosate than the glyphosate-susceptible (GS) accession. In anin vivoleaf-disk shikimate assay, leaf disks of GS kochia plants treated with 100-μM glyphosate accumulated 2.4- to 4.0-fold higher amounts of shikimate than the GR plants. The four GR accessions had 2.7 to 9.1 relativeEPSPSgene copies compared with the GS accession (<1EPSPSgene copies), and there was a linear relationship betweenEPSPSgene copy number and glyphosate resistance level (LD50values). The 2015 and 2016 GR kochia survey results indicated that about half of the collected populations from sugar beet fields in eastern Oregon had developed resistance to glyphosate whereas only one population from the Idaho collection was confirmed glyphosate resistant. This is the first confirmation of GR kochia in sugar beet fields in eastern Oregon and southwestern Idaho. Diversified weed control programs will be required to prevent further development and spread of GR kochia in sugar beet-based rotations in this region.

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

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.

scholarly journals No Impact of Increased EPSPS Gene Copy Number on Growth and Fecundity of Glyphosate-Resistant Kochia (Bassia scoparia)

Weed Science ◽  
2018 ◽  
Vol 67 (1) ◽  
pp. 22-28 ◽  
Author(s):  
O. Adewale Osipitan ◽  
J. Anita Dille
Keyword(s):  
Weed Management ◽  
Copy Number ◽  
Plant Biomass ◽  
Management Strategies ◽  
Gene Copy Number ◽  
Glyphosate Resistance ◽  
Gene Copy ◽  
Competitive Response ◽  
Epsps Gene

AbstractThe level of glyphosate resistance in kochia [Bassia scoparia(L.) A. J. Scott] was reported to be due to an increase in 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene copy number. A field study was conducted near Manhattan, KS, in 2014 and 2015 to evaluate the relationship between EPSPS gene copy number and growth and fecundity variables ofB. scopariaindividuals within suspected glyphosate-resistant (GR) populations from western Kansas. Initial assays of EPSPS gene copy and in vivo shikimate accumulation showed thatB. scopariapopulations from Finney (FN-R), Scott (SC-R), and Thomas (TH-R) counties were segregating for glyphosate resistance, with some individuals still being glyphosate susceptible (GS). A target-neighborhood competition approach was used to evaluate the competitive response of individual target plants with relatively low (classified as GS) and high (classified as GR) EPSPS gene copy number within the populations. There was no relationship observed between EPSPS gene copy number and vegetative or fecundity variables. There was no differential competitive response of target plant biomass to increasing neighbor density between individuals with low and high EPSPS gene copy number within each population. Lack of associated vegetative growth and fecundity cost to the increased EPSPS gene copy in the GRB. scopariaplants suggests that the plants are likely to persist in field populations, except when effective weed management strategies are adopted that would prevent their growth and seed production.

Glyphosate-Resistant Kochia (Kochia scoparia) in Kansas: EPSPS Gene Copy Number in Relation to Resistance Levels

Weed Science ◽  
2015 ◽  
Vol 63 (3) ◽  
pp. 587-595 ◽  
Author(s):  
Amar S. Godar ◽  
Phillip W. Stahlman ◽  
Mithila Jugulam ◽  
J. Anita Dille
Keyword(s):  
Copy Number ◽  
Gene Copy Number ◽  
Acetolactate Synthase ◽  
Outdoor Environment ◽  
Gene Copy ◽  
Geographically Dispersed ◽  
Epsps Gene ◽  
Whole Plant ◽  
Outdoor Environments ◽  
Control Failure

Reports of kochia control failure with glyphosate in western Kansas increased dramatically in the years following confirmed presence of glyphosate-resistant (GR) populations in 2007. In this study, progeny from 8 of 16 geographically dispersed kochia populations in western Kansas (seed collected in 2010) were confirmed to be resistant to glyphosate by conducting whole-plant dose-response (in greenhouse and/or outdoor environments) and shikimate-accumulation assays. Additionally, the relationship between 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene copy number and glyphosate resistance levels was investigated. A known glyphosate-susceptible (GS) kochia population from Ellis County, Kansas was used for comparison in all studies. Based on the herbicide rate that caused 50% reduction in biomass compared to untreated control (GR50) values, the 8 GR kochia populations were 4 to 11 times more resistant to glyphosate compared to the GS population. The GR50values of kochia populations were 1.58 to 1.85 times higher under an outdoor environment compared to when grown in the greenhouse. Glyphosate-treated leaf discs of the GS kochia plants accumulated consistently higher amounts of shikimate than those of the GR plants. Additionally, the GR plants with higher levels of resistance to glyphosate had higher EPSPS : acetolactate synthase (ALS) relative gene copy number compared to those with low levels of resistance.

EPSPSGene Amplification Primarily Confers Glyphosate Resistance among Arkansas Palmer amaranth (Amaranthus palmeri) Populations

Weed Science ◽  
2018 ◽  
Vol 66 (3) ◽  
pp. 293-300 ◽  
Author(s):  
Shilpa Singh ◽  
Vijay Singh ◽  
Amy Lawton-Rauh ◽  
Muthukumar V. Bagavathiannan ◽  
Nilda Roma-Burgos
Keyword(s):  
Copy Number ◽  
Gene Copy Number ◽  
Glyphosate Resistance ◽  
Resistance Mechanisms ◽  
Palmer Amaranth ◽  
Gene Copy ◽  
Amaranthus Palmeri ◽  
Resistance Level ◽  
Relative Copy Number ◽  
Gene Copies

AbstractResearch was conducted to determine whether resistance to glyphosate among Palmer amaranth (Amaranthus palmeriS. Watson) populations within the U.S. state of Arkansas was due solely to increasedEPSPSgene copy number and whether gene copy number is correlated with resistance level to glyphosate. One hundred and fifteenA. palmeriaccessions were treated with 840 g ae ha−1glyphosate. Twenty of these accessions, selected to represent a broad range of responses to glyphosate, underwent further testing. Seven of the accessions were controlled with this dose; the rest were resistant. The effective dose to cause 50% injury (ED50) for susceptible accessions ranged from 28 to 207 g ha−1. The glyphosate-resistant (GR) accessions had ED50values ranging from 494 to 1,355 g ha−1, a 3- to 48-fold resistance level compared with the susceptible standard (SS). The 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene relative copy number was determined for 20 accessions, 4 plants accession−1. Resistant plants from five GR accessions (38% of resistant plants tested) did not have increasedEPSPSgene copies. Resistant plants from the remaining eight GR accessions (62% of resistant plants tested) had 19 to 224 moreEPSPSgene copies than the SS. Among the accessions tested, injury declined 4% with every additionalEPSPScopy. ED50values were directly correlated withEPSPScopy number. The highly resistant accession MIS11-B had an ED50of 1,355 g ha−1and 150 gene copies. Partial sequences ofEPSPSfrom GR accessions withoutEPSPSamplification did not contain any of the known resistance-conferring mutations. Nearly 40% of GR accessions putatively harbor non–target site resistance mechanisms. Therefore, elevatedEPSPSgene copy number is associated with glyphosate resistance amongA. palmerifrom Arkansas.

scholarly journals Effect of EPSPS Gene Copy Number and Glyphosate Selection on Fitness of Glyphosate-Resistant Bassia Scoparia in The Field

2021 ◽  
Author(s):  
Charlemagne Ajoc Lim ◽  
Prashant Jha ◽  
Vipan Kumar ◽  
Alan T. Dyer
Keyword(s):  
Sugar Beet ◽  
Seed Production ◽  
Great Plains ◽  
Copy Number ◽  
Gene Copy Number ◽  
Reproductive Traits ◽  
Gene Copy ◽  
Epsps Gene ◽  
Gene Copies

Abstract The widespread evolution of glyphosate-resistant (GR) Bassia scoparia in the U.S. Great Plains poses a serious threat to the long-term sustainability of GR sugar beet. Glyphosate resistance in B. scoparia is due to an increase in the EPSPS (5-enolpyruvyl-shikimate-3-phosphate) gene copy number. The variation in EPSPS gene copies among individuals from within a single GR B. scoparia population indicated a differential response to glyphosate selection. We tested the hypothesis of reduced GR B. scoparia fitness (reproductive traits) to increasing glyphosate rates (applied as single or sequential applications) potentially experienced within a GR sugar beet field. The variation in EPSPS gene copy number and total glyphosate rate (single or sequential applications) did not influence any of the reproductive traits of GR B. scoparia, except seed production. Sequential applications of glyphosate with a total rate of 2,214 g ae ha− 1 or higher prevented seed production in B. scoparia plants with 2–4 (low levels of resistance) and 5–6 (moderate levels of resistance) EPSPS gene copies. Timely sequential applications of glyphosate (full recommended rates) can potentially slow down the evolution of GR B. scoparia with low to moderate levels of resistance (2–6 EPSPS gene copies), but any survivors (highly-resistant individuals with ≥ 8 EPSPS gene copies) need to be mechanically removed before flowering from GR sugar beet fields. This research warrants the need to adopt ecologically based, multi-tactic strategies to reduce exposure of B. scoparia to glyphosate in GR sugar beet.

scholarly journals Defense by duplication: The relation between phenotypic glyphosate resistance and EPSPS gene copy number variation in Amaranthus palmeri

2021 ◽  
Author(s):  
Sarah B Yakimowski ◽  
Zachary Teitel ◽  
Christina M. Caruso
Keyword(s):  
Copy Number Variation ◽  
Copy Number ◽  
Gene Copy Number ◽  
Glyphosate Resistance ◽  
Gene Copy ◽  
Quantitative Relation ◽  
Stabilizing Selection ◽  
Amaranthus Palmeri ◽  
Gene Copy Number Variation ◽  
Number Variation

Gene copy number variation (CNV) has been increasingly associated with organismal responses to environmental stress, but we know little about the quantitative relation between CNV and phenotypic variation. In this study we quantify variation in EPSPS (5-enolpyruvylshikimate-3-phosphate synthase) copy number using digital drop PCR and variation in phenotypic glyphosate resistance in 22 populations of Amaranthus palmeri (Palmer Amaranth), a range-expanding agricultural weed. Overall, we detected a significant positive relation between population mean copy number and mean resistance. The majority of populations exhibited high glyphosate resistance, yet maintained low-resistance individuals resulting in bimodality in many populations. We investigated linear and threshold models for the relation between copy number and resistance, and found evidence for a threshold of ~15 EPSPS copies: there was a steep increase in resistance before the threshold, followed by a much shallower slope. Moreover, as copy number increases, the range of variation in resistance decreases. This suggests a working hypothesis that as EPSPS copies and dosage increases, negative epistatic interactions may be compensated. We detected a quadratic relation between mean resistance and variation (s.d.) in resistance, consistent with the prediction that as phenotypic resistance increases in populations, stabilizing selection decreases variation in the trait. Finally, patterns of variation across the landscape are consistent with less variation among populations in mean copy number / resistance in Georgia where glyphosate resistance was first detected, and wider variation among populations in resistance and copy number in a more northern state where resistance evolution may be at a younger evolutionary state.

scholarly journals Industrial yeasts display tandem gene iteration at the CUP1 region.

1983 ◽  
Vol 3 (8) ◽  
pp. 1353-1361 ◽  
Author(s):  
J W Welch ◽  
S Fogel ◽  
G Cathala ◽  
M Karin
Keyword(s):  
Copy Number ◽  
Repeat Unit ◽  
Gene Copy Number ◽  
Copper Resistance ◽  
Gene Copy ◽  
Copper Binding ◽  
Resistance Level ◽  
Enhanced Production ◽  
Inducible Protein ◽  
Industrial Yeasts

The gene copy number at the CUP1 locus and the resistance level to external copper was directly correlated in five wild-type commercial Saccharomyces strains. An increased copy number of the CUP1 gene leads to increased accumulation of chelatin mRNA, which codes for a low-molecular-weight, copper-binding protein. The enhanced production of this rapidly inducible protein mediates resistance of the cell to copper. Industrial yeasts exhibit homologies to the amplified copper resistance repeat unit found in laboratory strains. However, the extent of tandem iteration is strain dependent, and the repetitious unit is either 1.7 or 1.5 kilobases in length compared with the 2.0-kilobase unit in laboratory strains. Strain 522 (Montrachet) contains two chromosome VIII segments distinguishable by their numbers of repeat units (2 and 11) and the size of the units (1.5 and 1.7 kilobases). Distillers yeast 513 carries a 1.5-kilobase repeat unit on each homologous chromosome, although they contain nine and five iterations, respectively.

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