Roundup Ready Crops Research Articles

English

Following the introduction of genetically-engineered glyphosate-resistant (GEGR) crops, commercially known as Roundup Ready (RR), no pesticide’s active principle has been used as much as glyphosate; yet its safety measures have been sternly disputed.  After its classification by the International Agency for Research on Cancer (IARC) as probably carcinogenic to humans in 2015, scientists, activists, regulators and the general public revisited voluminous studies that outweighed the risk of this herbicide and raised ferocious concerns that warranted serious attention.  Recently published studies on glyphosate established at least four toxicological principles. First, glyphosate exhibited severe mammalian toxicity at concentrations orders of magnitude lower than its regulatory-promulgated ‘No Observed Adverse Effect Level’ (NOAEL) or even its ‘Chronic Reference Dose’ (cRfD) and ‘Acceptable Daily Intake’ (ADI).  Second, even though not transparently scrutinized or officially required for toxicological testing and risk assessment, glyphosate co-formulants and glyphosate-based herbicides (GBHs) are orders of magnitude more toxic than the principle active ingredient alone. Third, glyphosate and GBHs are cytotoxic and endocrine disruptors, and the latter explains why ultra low concentrations - yet environmentally relevant-cause severe chronic toxicity. Fourth, the endocrine disruption likely leads to epigenotoxicity that may be extended to offspring and unexposed descending generations.  Taken all together, it can be fairly said that confidence in the regulatory-certified ADI values is highly eroded. To resolve the paradoxical discrepancy between regulatory safety measures and elicited toxicities at concentrations far below these measures, ADI was refined using two safety or adjustment factors.  Together, these two factors scale down ADI by four orders of magnitude and bring it to an Adjusted ADI (AADI) value of 2.5 ng/kg bw/day. Contrary to regulatory ADI, the new AADI successfully explains many research findings which demonsted severe mammalian toxicity at concentrations in the neighborhood of nanograms a.i./kg bw/day. This distills confidence in the new AADI value, as well as the magnitude of the proposed safety factors.  Glyphosate uses as per human capita, in two countries representing the extremes of adopting RR crops (the USA) or not-adopting these crops (Egypt), were compared. The comparison confirms the association between growing RR crops and the escalated use of glyphosate, and shows that the American public is likely exposed to glyphosate residue at forty times higher levels than the Egyptian public.   Key words: Acceptable daily intake, adjuvant, chronic reference dose, co-formulants, food quality protection act, hazard, glyphosate, glyphosate-based herbicides, no observed adverse effect level, risk, roundup, roundup ready crops.

Review of Biological Impacts of Genetically Engineered Crops and Neonicotinoid Treated Seed Use on Staten Island

Genetically modified organism (GMO) crops particularly Roundup Ready Crops have been widely used in commercial agriculture in the United States in general and Staten Island in particular. However, its use has promoted concerns about the potential environmental effects of this technology. Therefore, this work was initiated to review impact of GE crops and Neonicotinoid to biodiversity, special focus on bees, birds, and super weeds development at Satan Island. Glyphosate herbicide is now widely used for growing Roundup Ready crop, like maize and soy bean. Scientists reported that using glyphosate herbicide by far better than using the previously used herbicide to the environment and biodiversity. It is also known that super weed may develop through gene flow from Roundup Ready Crops to its wild relatives and develop resistance against roundup. However, this might not be a problem in Staten Island where there is no wild relative species for widely grown Roundup Ready Crops like corn and alfaalfa.With regards to Neonicotinoids, it has lower toxicity to mammals like birds, and fish than other non-target insect species specially bees and other pollinator. The effect of Neonicotinoids to non-target species can be minimized using Fluent Agent in seed coating the which reduces dust contamination. Therefore, the use of Genetically Engineered Crops and Neonicotinoid Treated Seed needs special care and management in order to minimize its damage to non-target insect species.

Review of GMO safety assessment studies: glyphosate residues in Roundup Ready crops is an ignored issue

Genetically modified glyphosate-tolerant cultivar varieties have been a commercial success widely known as Roundup Ready plants. As new glyphosate-tolerant varieties are introduced to satisfy agriculture demand, it is relevant to review the scientific evidence that documents the quality and safety of such biotechnology. Assessments of genetically modified glyphosate-tolerant plants are partly based on the reports from laboratory comparisons with non-modified plants (near-isogenic relatives). Such comparative testing is typically performed as analysis of plant material composition and in animal feeding studies. The material for testing is typically produced in test-fields set up as model environments. Most of this research is planned, performed and reported by researchers employed by biotech industry companies. The present paper aims to: (1) review 15 reports on compositional analyses of glyphosate-tolerant cultivars and 15 reports from animal feeding studies, (2) discuss recent data indicating glyphosate residue in Roundup Ready soybean, (3) outline recent developments of cultivars with increased tolerance to glyphosate. The reviewed industry studies show methodological flaws: glyphosate-tolerant GM crops are designed for use with glyphosate herbicide. However, glyphosate herbicides are often not applied in test-study cultivation. In the studies where glyphosate herbicides were applied to growing plants, the produced plant material was not analyzed for glyphosate residues. This review has failed to identify industry studies that mention glyphosate residues in glyphosate-tolerant plants. This indicates that questions and evidence of importance for regulatory assessment have been systematically ignored. Independent research has investigated this issue and found that glyphosate-tolerant plants accumulate glyphosate residues at unexpected high levels. Glyphosate residues are found to have potential to affect plant material composition. Furthermore, these residues are passed on to consumers. Industry studies are not sufficient for regulation. Despite decades of risk assessments and research in this field, specific unanswered questions relating to safety and quality aspects of food and feed from GM crops need to be addressed by regulators. Independent research gives important supplementary insight.

Detection of the cp4 epsps Gene in Maize Line NK603 and Comparison of Related Protein Structures: An Advanced Undergraduate Experiment

A flexible, rigorous laboratory experiment for upper-level biochemistry undergraduates is described that focuses on the Roundup Ready maize line. The work is appropriate for undergraduate laboratory courses that integrate biochemistry, molecular biology, or bioinformatics. In this experiment, DNA is extracted and purified from maize kernel and leaf samples collected from a Roundup Ready maize grower’s field. A small segment of DNA (108 base pairs) specific to the Roundup Ready transgene that codes for CP4 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS) is amplified with polymerase chain reaction (PCR) to detect the presence of the gene in the maize samples. Students additionally choose a protein closely related to CP4 EPSPS as determined by amino acid sequence alignments. The selected amino acid sequences are submitted to an online protein modeling program where students compare their protein with the herbicide-resistant enzyme found in Roundup Ready crops. This experimental paradigm gives students a physical appreciation for the central dogma of biology, as they are exposed to products derived from the replication, transcription, and translation events belonging to a genetically modified crop. The PCR portion of the laboratory allows students to perform an in vitro replication of a portion of the NK603 transgene and identify the segment via ultraviolet radiation. In direct connection to the PCR portion, the protein structure elucidation gives rise to the central ideas of evolution—that slight changes in the genetic code of DNA, translated into proteins, produce novel protein structures with significantly different function.

Effect of the cp4-epsps Gene on Metal Bioavailability in Maize and Soybean Using Bionic Gastrointestinal Tracts and ICP-MS Determination

The transformation and metabolism of dietary compounds are affected significantly by gut microbiota. Hence, gut microbiota are used to improve bionic gastrointestinal tracts. The effect of the cp4-epsps gene on metal bioavailability was proved by the comparison of the affinity-liposome metal content ratio (AMCR) in transgenic and conventional crops. The bioavailability of V, Mn, Co, Ga, Ag, Ba, and Pb in roundup ready soybean decreased significantly because the ratio of AMCR (R(AMCR)) in the transgenic crop and its corresponding conventional type ranged from 0.36 to 0.69. In roundup ready maize, metal bioavailability decreased for Li and Cr (i.e., R(AMCR) was 0.26 and 0.39, respectively) but increased for V, Co, and Pb (i.e., R(AMCR) was 1.48, 2.07, and 2.12, respectively). Compared with conventional crops, safe dosage and maximum consumption of roundup ready crops were 1.59 times for soybean and 0.78 times for maize.

Monsanto and the Per Se Illegal Rule for Bundled Discounts

Recent statistics indicate that 90% of the soybeans and 70% of the corn and cotton grown in the United States are Roundup Ready crops. The Roundup Ready gene, patented by Monsanto, allows those crops to withstand application of Roundup, an herbicide originally produced solely by Monsanto with the active ingredient of glyphosate, which kills weeds on contact. Although Monsanto’s patent on the Roundup herbicide expired in 2000, the company’s business practices made it an industry giant in both the seed and herbicide markets. Monsanto requires that farmers sign a technology agreement when purchasing Roundup Ready seeds that restricts the purchase of herbicide to products produced by Monsanto. The company also heavily encourages farmers to purchase their brand of herbicide with Roundup Ready seeds through discounting programs. This note will examine whether Monsanto should be held accountable for unlawful bundling under a theoretical judicial standard that finds both tying and bundling per se illegal — with no need to prove further consumer forcing. The argument is based on Einer Elhauge’s recent critique of the rule of reason, a rule which states that tying and bundling schemes are illegal only if there is proof of substantial market foreclosure. Application of the rule of reason, the currently favored judicial approach, over the rule of per se illegality has made it virtually impossible for challengers to successfully dispute tying and bundling schemes. Such schemes should be susceptible to judicial scrutiny to protect consumer welfare — precisely the goal of the Sherman Antitrust Act.

Structural Basis of Glyphosate Tolerance Resulting from Mutations of Pro101 in Escherichia coli 5-Enolpyruvylshikimate-3-phosphate Synthase

Glyphosate, the world's most used herbicide, is a massive success because it enables efficient weed control with minimal animal and environmental toxicity. The molecular target of glyphosate is 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), which catalyzes the sixth step of the shikimate pathway in plants and microorganisms. Glyphosate-tolerant variants of EPSPS constitute the basis of genetically engineered herbicide-tolerant crops. A single-site mutation of Pro(101) in EPSPS (numbering according to the enzyme from Escherichia coli) has been implicated in glyphosate-resistant weeds, but this residue is not directly involved in glyphosate binding, and the basis for this phenomenon has remained unclear in the absence of further kinetic and structural characterization. To probe the effects of mutations at this site, E. coli EPSPS enzymes were produced with glycine, alanine, serine, or leucine substituted for Pro(101). These mutant enzymes were analyzed by steady-state kinetics, and the crystal structures of the substrate binary and substrate.glyphosate ternary complexes of P101S and P101L EPSPS were determined to between 1.5- and 1.6-A resolution. It appears that residues smaller than leucine may be substituted for Pro(101) without decreasing catalytic efficiency. Any mutation at this site results in a structural change in the glyphosate-binding site, shifting Thr(97) and Gly(96) toward the inhibitor molecule. We conclude that the decreased inhibitory potency observed for glyphosate is a result of these mutation-induced long-range structural changes. The implications of our findings concerning the development and spread of glyphosate-resistant weeds are discussed.

Molecular basis for the herbicide resistance of Roundup Ready crops.

The engineering of transgenic crops resistant to the broad-spectrum herbicide glyphosate has greatly improved agricultural efficiency worldwide. Glyphosate-based herbicides, such as Roundup, target the shikimate pathway enzyme 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase, the functionality of which is absolutely required for the survival of plants. Roundup Ready plants carry the gene coding for a glyphosate-insensitive form of this enzyme, obtained from Agrobacterium sp. strain CP4. Once incorporated into the plant genome, the gene product, CP4 EPSP synthase, confers crop resistance to glyphosate. Although widely used, the molecular basis for this glyphosate-resistance has remained obscure. We generated a synthetic gene coding for CP4 EPSP synthase and characterized the enzyme using kinetics and crystallography. The CP4 enzyme has unexpected kinetic and structural properties that render it unique among the known EPSP synthases. Glyphosate binds to the CP4 EPSP synthase in a condensed, noninhibitory conformation. Glyphosate sensitivity can be restored through a single-site mutation in the active site (Ala-100-Gly), allowing glyphosate to bind in its extended, inhibitory conformation.

DETOX LETS CROPS RESIST HERBICIDE

CROPS ENGINEERED TO PROduce an enzyme capable of N -acetylating the widely used, environmentally friendly herbicide glyphosate—a modification that renders glyphosate nontoxic—are resistant to the weed killer, according to a new study. If it's commercialized, this novel strategy could spark competition and further innovation in the lucrative market for glyphosate-tolerant crops, worth nearly $2.2 billion in 2002. The world's top-selling herbicide, glyphosate —originally trademarked by Monsanto as Roundup—kills weeds by inhibiting an enzyme that plants rely on to biosynthesize the aromatic amino acids they require to grow. Glyphosate is widely used in combination with Monsanto-brand Roundup Ready crops, which are engineered to contain a glyphosate-immune microbial version of this enzyme. This allows farmers to spray entire fields with the herbicide, killing the weeds but not their crops. Now, plant scientist Linda A. Castle of Redwood City, Calif.-based Verdia and her colleagues at Verdia and Pioneer Hi-Bre...