Dataset Information

Evaluation of glyphosate resistance in Arabidopsis thaliana expressing an altered target site EPSPS.

ABSTRACT:

Background

Glyphosate-resistant goosegrass has recently evolved and is homozygous for the double mutant of EPSPS (T₁₀₂ I, P₁₀₆ S or TIPS). These same mutations combined with EPSPS overexpression, have been used to create transgenic glyphosate-resistant crops. Arabidopsis thaliana (Wt EPSPS K_i ? 0.5 ?M) was engineered to express a variant AtEPSPS-T₁₀₂ I, P₁₀₆ A (TIPA K_i = 150 ?M) to determine the resistance magnitude for a more potent variant EPSPS that might evolve in weeds.

Results

Transgenic A. thaliana plants, homozygous for one, two or four copies of AtEPSPS-TIPA, had resistance (IC₅₀ values, R/S) as measured by seed production ranging from 4.3- to 16-fold. Plants treated in reproductive stage were male sterile with a range of R/S from 10.1- to 40.6-fold. A significant hormesis (? 63% gain in fresh weight) was observed for all genotypes when treated at the initiation of reproductive stage with 0.013 kg ha^-1 . AtEPSPS-TIPA enzyme activity was proportional to copy number and correlated with resistance magnitude.

Conclusions

A. thaliana, as a model weed expressing one copy of AtEPSPS-TIPA (300-fold more resistant), had only 4.3-fold resistance to glyphosate for seed production. Resistance behaved as a single dominant allele. Vegetative tissue resistance was 4.7-fold greater than reproductive tissue resistance and was linear with gene copy number. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

SUBMITTER: Sammons RD

PROVIDER: S-EPMC5901408 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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Publications

Evaluation of glyphosate resistance in Arabidopsis thaliana expressing an altered target site EPSPS.

Sammons R Douglas RD You Jinsong J Qi Youlin Y Flasinski Stanislaw S Kavanaugh Christina C Washam Jeannie J Ostrander Elizabeth E Wang Dafu D Heck Greg G

Pest management science 20170907 5

<h4>Background</h4>Glyphosate-resistant goosegrass has recently evolved and is homozygous for the double mutant of EPSPS (T102 I, P106 S or TIPS). These same mutations combined with EPSPS overexpression, have been used to create transgenic glyphosate-resistant crops. Arabidopsis thaliana (Wt EPSPS Ki ∼ 0.5 μM) was engineered to express a variant AtEPSPS-T102 I, P106 A (TIPA Ki = 150 μM) to determine the resistance magnitude for a ...[more]

PMID: 28677849

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Project description:Glyphosate has been the most intensely herbicide used worldwide for decades, and continues to be a single tool for controlling weeds in woody crops. However, the adoption of this herbicide in a wide range of culture systems has led to the emergence of resistant weeds. Glyphosate has been widely used primarily on citrus in the Caribbean area, but a study of resistance in the Caribbean islands of Cuba and the Dominican Republic has never been carried out. Unfortunately, Parthenium hysterophorus has developed glyphosate-resistance in both islands, independently. The resistance level and mechanisms of different P. hysterophorus accessions (three collected in Cuba (Cu-R) and four collected in the Dominican Republic (Do-R) have been studied under greenhouse and laboratory conditions. In in vivo assays (glyphosate dose causing 50% reduction in above-ground vegetative biomass and survival), the resistance factor levels showed susceptible accessions (Cu-S ? Do-S), low-resistance accessions (Cu-R3 < Do-R4), medium-resistance accessions (Do-R3 < Cu-R2 < Do-R2) and high-resistance accessions (Do-R1 < Cu-R1). In addition, the resistance factor levels were similar to those found in the shikimic acid accumulation at 1000 ?M of glyphosate (Cu-R1 ? Do-R1 > Do-R2 > Cu-R2 > Do-R3 > Do-R4 > Cu-R3 >> Cu-S ? Do-S). Glyphosate was degraded to aminomethylphosphonic acid, glyoxylate and sarcosine by >88% in resistant accessions except in Cu-R3 and Do-R4 resistant accessions (51.12 and 44.21, respectively), whereas a little glyphosate (<9.32%) was degraded in both susceptible accessions at 96 h after treatment. There were significant differences between P. hysterophorus accessions in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity enzyme with and without different glyphosate rates. The R accessions showed values of between 0.026 and 0.21 ?mol ?g-1 TSP protein min-1 basal EPSPS activity values with respect to the S (0.024 and 0.025) accessions. The same trend was found in the EPSPS enzyme activity treated with glyphosate, where a higher enzyme activity inhibition (glyphosate ?M) corresponded to greater resistance levels in P. hysterophorus accessions. One amino acid substitution was found at position 106 in EPSPS, consisting of a proline to serine change in Cu-R1, Do-R1 Do-R2. The above-mentioned results indicate that high resistance values are determined by the number of defense mechanisms (target-site and non-target-site resistance) possessed by the different P. hysterophorus accessions, concurrently.

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Dataset Information

Evaluation of glyphosate resistance in Arabidopsis thaliana expressing an altered target site EPSPS.

Background

Results

Conclusions

Publications

Evaluation of glyphosate resistance in Arabidopsis thaliana expressing an altered target site EPSPS.

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