Rice (Oryza sativa L.) containing the bar gene is compositionally equivalent to the nontransgenic counterpart

Identification and Expression Analysis of EPSPS and BAR Families in Cotton

Weeds seriously affect the yield and quality of crops. Because manual weeding is time-consuming and laborious, the use of herbicides becomes an effective way to solve the harm caused by weeds in fields. Both 5-enolpyruvyl shikimate-3-phosphate synthetase (EPSPS) and acetyltransferase genes (bialaphos resistance, BAR) are widely used to improve crop resistance to herbicides. However, cotton, as the most important natural fiber crop, is not tolerant to herbicides in China, and the EPSPS and BAR family genes have not yet been characterized in cotton. Therefore, we explore the genes of these two families to provide candidate genes for the study of herbicide resistance mechanisms. In this study, 8, 8, 4, and 5 EPSPS genes and 6, 6, 5, and 5 BAR genes were identified in allotetraploid Gossypium hirsutum and Gossypium barbadense, diploid Gossypium arboreum and Gossypium raimondii, respectively. Members of the EPSPS and BAR families were classified into three subgroups based on the distribution of phylogenetic trees, conserved motifs, and gene structures. In addition, the promoter sequences of EPSPS and BAR family members included growth and development, stress, and hormone-related cis-elements. Based on the expression analysis, the family members showed tissue-specific expression and differed significantly in response to abiotic stresses. Finally, qRT-PCR analysis revealed that the expression levels of GhEPSPS3, GhEPSPS4, and GhBAR1 were significantly upregulated after exogenous spraying of herbicides. Overall, we characterized the EPSPS and BAR gene families of cotton at the genome-wide level, which will provide a basis for further studying the functions of EPSPS and BAR genes during growth and development and herbicide stress.

Development of a rapid detection method for genetically modified rice using the ultra-fast PCR system

Genetically modified (GM) rice varieties containing traits such as tolerance to abiotic stress and resistance against pests and diseases continue to be developed. However, contamination incidents from unauthorized GM rice varieties have been encountered. To date, no GM rice crop has been authorized for consumption and/or commercialization in Korea. Therefore, to enhance safety management of unauthorized genetically modified organisms (GMOs), accurate and reliable detection methods are needed to identify GMOs in crops or products. In this study, we developed rapid detection methods for GM rice events (Bt63, KMD1, Kefeng6, Kefeng8, and LLRice62) using ultra-fast PCR system. Ultra-fast PCR is a state-of-the-art technology and decreases PCR run-times dramatically. However, the ultra-fast PCR is not widely used in GMO analysis. Thus, we designed a detection method for five events of GM rice and confirmed them by performing specificity, sensitivity, and applicability assays. All results demonstrate that the ultra-fast PCR system is a specific, sensitive, and reliable method to identify and monitor GM rice events. Additionally, it can be utilized as a rapid and simple method for GMO analysis in crops or processed products. This study can be used as a reference for future research on new analysis methods of unauthorized GMOs.

Compositional analysis of transgenic Bt-chickpea resistant to Helicoverpa armigera

Transgenic chickpeas expressing high levels of a truncated version of the cry1Ac (trcry1Ac) gene conferred complete protection to Helicoverpa armigera in the greenhouse. Homozygous progeny of two lines, Cry1Ac.1 and Cry1Ac.2, had similar growth pattern and other morphological characteristics, including seed yield, compared to the non-transgenic counterpart; therefore, seed compositional analysis was carried out. These selected homozygous chickpea lines were selfed for ten generations along with the non-transgenic parent under contained conditions. A comparative seed composition assessment, seed storage proteins profiling, and in vitro protein digestibility were performed to confirm that these lines do not have significant alterations in seed composition compared to the parent. Our analyses showed no significant difference in primary nutritional composition between transgenic and non-transgenic chickpeas. In addition, the seed storage protein profile also showed no variation between the transgenic chickpea lines. Seed protein digestibility assays using simulated gastric fluid revealed a similar rate of digestion of proteins from the transgenic trcry1Ac lines compared to the non-transgenic line. Thus, our data suggest no unintended changes in the seed composition of transgenic chickpea expressing a trcry1Ac gene.

Equivalence Testing Approaches in Genetically Modified Organism Risk Assessment

Since 2011, the European Food Safety Authority (EFSA) has implemented combined difference and equivalence testing of agronomic, phenotypic, and composition data in the risk assessment of genetically modified crops. A short perspective is provided on misunderstandings that have shown up in published criticisms of the approach to equivalence testing, different viewpoints regarding the questions to be answered, and new developments in statistical modeling.

Equivalence limit scaled differences for untargeted safety assessments: Comparative analyses to guard against unintended effects on the environment or human health of genetically modified maize

Safety assessments guard against unintended effects for human health and the environment. When new products are compared with accepted reference products by broad arrays of measurements, statistical analyses are usually summarised by significance tests or confidence intervals per endpoint. The traditional approach is to test for statistical significance of differences. However, absence or presence of significant differences is not a statement about safety. Equivalence limits are essential for safety assessment. We propose graphs to present the results of equivalence tests over the array of endpoints. It is argued that plots of the equivalence limit scaled difference (ELSD) are preferable over plots of the standardised effect size (SES) used previously for similar assessments. The ELSD method can be used either with externally specified equivalence limits or with equivalence limits estimated from (historical) data. The method is illustrated with two examples: first, environmental safety of MON810 Bt maize was assessed using field trial count data of arthropods; second, human safety of herbicide tolerant NK603 maize was assessed using haematological, biochemical and organ weight data from a 90-day rat feeding study. All assessed endpoints were classified in EFSA equivalence categories I or II, implying full equivalence or equivalence more likely than not.

Strategies to Evaluate the Safety of Bioengineered Foods

A number of genetically modified (GM) crops bioengineered to express agronomic traits including herbicide resistance and insect tolerance have been commercialized. Safety studies conducted for the whole grains and food and feed fractions obtained from GM crops (i.e., bioengineered foods) bear similarities to and distinctive differences from those applied to substances intentionally added to foods (e.g., food ingredients). Similarities are apparent in common animal models, route of exposure, duration, and response variables typically assessed in toxicology studies. However, because of differences in the nutritional and physical properties of food ingredients and bioengineered foods and in the fundamental goals of the overall safety assessment strategies for these different classes of substances, there are recognizable differences in the individual components of the safety assessment process. The fundamental strategic difference is that the process for food ingredients is structured toward quantitative risk assessment whereas that for bioengineered foods is structured for the purpose of qualitative risk assessment. The strategy for safety assessment of bioengineered foods focuses on evaluating the safety of the transgenic proteins used to impart the desired trait or traits and to demonstrate compositional similarity between the grains of GM and non-GM comparator crops using analytical chemistry and, in some cases, feeding studies. Despite these differences, the similarities in the design of safety studies conducted with bioengineered foods should be recognized by toxicologists. The current paper reviews the basic principles of safety assessment for bioengineered foods and compares them with the testing strategies applied to typical food ingredients. From this comparison it can be seen that the strategies used to assess the safety of bioengineered foods are at least as robust as that used to assess the safety of typical food ingredients.

Comparative evaluation of nutritional compositions between transgenic rice harboring the CaMsrB2 gene and the conventional counterpart

As a part of a safety assessment of new transgenic crops, compositional equivalence studies between transgenic crops with non-transgenic comparators are almost universally required. This study was conducted to compare nutritional profiles of proximate composition, and fatty acid, amino acid, mineral, and vitamin contents, and anti-nutrients, between transgenic drought-tolerant Agb0103 rice harboring the pepper methionine sulfoxide reductase B2 gene CaMsrB2 and the parental rice cultivar, 'Ilmi' as a non-transgenic control. Both transgenic and non-transgenic rice were grown and harvested in 2 different locations. Proximate compositions of moisture, starch, protein, lipid, and ash content of Agb0103 rice were similar to parental non-transgenic rice. There were no differences between transgenic and non-transgenic rice with respect to the whole nutritional composition, except for minor locality differences for a few nutritional components. Agb0103 rice with improved resistance to drought is nutritionally equivalent to the parental rice cultivar.

Comparative nutritional compositions and proteomics analysis of transgenic Xa21 rice seeds compared to conventional rice

Transgenic rice expressing the Xa21 gene have enhanced resistant to most devastating bacterial blight diseases caused by Xanthomonas oryzae pv. oryzae (Xoo). However, identification of unintended modifications, owing to the genetic modification, is an important aspect of transgenic crop safety assessment. In this study, the nutritional compositions of seeds from transgenic rice plants expressing the Xa21 gene were compared against non-transgenic rice seeds. In addition, to detect any changes in protein translation levels as a result of Xa21 gene expression, rice seed proteome analyses were also performed by two-dimensional gel electrophoresis. No significant differences were found in the nutritional compositions (proximate components, amino acids, minerals, vitamins and anti-nutrients) of the transgenic and non-transgenic rice seeds. Although gel electrophoresis identified 11 proteins that were differentially expressed between the transgenic and non-transgenic seed, only one of these (with a 20-fold up-regulation in the transgenic seed) shows nutrient reservoir activity. No new toxins or allergens were detected in the transgenic seeds.

Safety assessment of foods from genetically modified crops in countries with developing economies

Population growth particularly in countries with developing economies will result in a need to increase food production by 70% by the year 2050. Biotechnology has been utilized to produce genetically modified (GM) crops for insect and weed control with benefits including increased crop yield and will also be used in emerging countries. A multicomponent safety assessment paradigm has been applied to individual GM crops to determine whether they as safe as foods from non-GM crops. This paper reviews methods to assess the safety of foods from GM crops for safe consumption from the first generation of GM crops. The methods can readily be applied to new products developed within country and this paper will emphasize the concept of data portability; that safety data produced in one geographic location is suitable for safety assessment regardless of where it is utilized.

Genotypic and Environmental Impact on Natural Variation of Nutrient Composition in 50 Non Genetically Modified Commercial Maize Hybrids in North America

This study was designed to assess natural variation in composition and metabolites in 50 genetically diverse non genetically modified maize hybrids grown at six locations in North America. Results showed that levels of compositional components in maize forage were affected by environment more than genotype. Crude protein, all amino acids except lysine, manganese, and β-carotene in maize grain were affected by environment more than genotype; however, most proximates and fibers, all fatty acids, lysine, most minerals, vitamins, and secondary metabolites in maize grain were affected by genotype more than environment. A strong interaction between genotype and environment was seen for some analytes. The results could be used as reference values for future nutrient composition studies of genetically modified crops and to expand conventional compositional data sets. These results may be further used as a genetic basis for improvement of the nutritional value of maize grain by molecular breeding and biotechnology approaches.

Insect-protected event DAS-81419-2 soybean (Glycine max L.) grown in the United States and Brazil is compositionally equivalent to nontransgenic soybean

The transgenic soybean event DAS-81419-2 contains genes that encode the Cry1F, Cry1Ac, and PAT proteins. Cry1F and Cry1Ac provide protection against key lepidopteran insect pests, while PAT confers tolerance to the herbicide glufosinate. To satisfy regulatory requirements for the safety evaluation of transgenic crops, studies were conducted in the United States and Brazil to evaluate the nutrient and antinutrient composition of event DAS-81419-2 soybean. On the basis of the results of these studies, event DAS-81419-2 soybean is compositionally equivalent to nontransgenic soybean. This conclusion concurs with numerous other published studies in soybean and other crops where compositional equivalence between the transgenic crop and its nontransgenic comparator has been demonstrated.

A three generation reproduction study with Sprague-Dawley rats consuming high-amylose transgenic rice

The transgenic rice line (TRS) enriched with amylose and resistant starch (RS) was developed by antisense RNA inhibition of starch-branching enzymes. Cereal starch with high amylose has a great benefit on human health through its resistant starch. In order to evaluate the effect of transgenic rice on rats, the rats were fed diets containing 70% TRS rice flour, its near-isogenic rice flour or the standard diet as the control through three generations. In the present study, clinical performance, reproductive capacity and pathological responses including body weight, food consumption, reproductive data, hematological parameters, serum chemistry components, organ relative weights and histopathology were examined. Some statistically significant differences were observed in rats consuming the high amylose rice diet when compared to rats fed the near-isogenic control rice diet or the conventional (non-rice) standard diet. These differences were generally of small magnitude, appeared to be random in nature, and were within normal limits for the strain of rat used, and were therefore not considered to be biologically meaningful or treatment related.

Assessment of peanut quality and compositional characteristics among transgenic sclerotinia blight-resistant and non-transgenic susceptible cultivars

This study presents the results of a comparison that includes an analysis of variance and a canonical discriminant analysis to determine compositional equivalence and similarity between transgenic, sclerotinia blight-resistant and non-transgenic, susceptible cultivars of peanut in 3 years of field trials. Three Virginia-type cultivars (NC 7, Wilson, and Perry) and their corresponding transgenic lines (N70, W73, and P39) with a barley oxalate oxidase gene were analyzed for differences in key mineral nutrients, fatty acid components, hay constituents, and grade characteristics. Results from both analyses demonstrated that transgenic lines were compositionally similar to their non-transgenic parent cultivar in all factors as well as market-grade characteristics and nutritional value. Transgenic lines expressing oxalate oxidase for resistance to sclerotinia blight were substantially equivalent to their non-transgenic parent cultivar in quality and compositional characteristics.

Unintended compositional changes in genetically modified (GM) crops: 20 years of research

The compositional equivalency between genetically modified (GM) crops and nontransgenic comparators has been a fundamental component of human health safety assessment for 20 years. During this time, a large amount of information has been amassed on the compositional changes that accompany both the transgenesis process and traditional breeding methods; additionally, the genetic mechanisms behind these changes have been elucidated. After two decades, scientists are encouraged to objectively assess this body of literature and determine if sufficient scientific uncertainty still exists to continue the general requirement for these studies to support the safety assessment of transgenic crops. It is concluded that suspect unintended compositional effects that could be caused by genetic modification have not materialized on the basis of this substantial literature. Hence, compositional equivalence studies uniquely required for GM crops may no longer be justified on the basis of scientific uncertainty.

Safety of GM crops: compositional analysis

The compositional analysis of genetically modified (GM) crops has continued to be an important part of the overall evaluation in the safety assessment program for these materials. The variety and complexity of genetically engineered traits and modes of action that will be used in GM crops in the near future, as well as our expanded knowledge of compositional variability and factors that can affect composition, raise questions about compositional analysis and how it should be applied to evaluate the safety of traits. The International Life Sciences Institute (ILSI), a nonprofit foundation whose mission is to provide science that improves public health and well-being by fostering collaboration among experts from academia, government, and industry, convened a workshop in September 2012 to examine these and related questions, and a series of papers has been assembled to describe the outcomes of that meeting.

Pleiotropic effects of herbicide-resistance genes on crop yield: a review

The rapid adoption of genetically engineered herbicide-resistant crop varieties (HRCVs)-encompassing 83% of all GM crops and nearly 8% of the worldwide arable area-is due to technical efficiency and higher returns. Other herbicide-resistant varieties obtained from genetic resources and mutagenesis have also been successfully released. Although the benefit for weed control is the main criteria for choosing HRCVs, the pleiotropic costs of genes endowing resistance have rarely been investigated in crops. Here the available data of comparisons between isogenic resistant and susceptible varieties are reviewed. Pleiotropic harmful effects on yield are reported in half of the cases, mostly with resistance mechanisms that originate from genetic resources and mutagenesis (atrazine in oilseed rape and millet, trifluralin in millet, imazamox in cotton) rather than genetic engineering (chlorsulfuron and glufosinate in some oilseed rape varieties, glyphosate in soybean). No effect was found for sethoxydim and bromoxynil resistance. Variable minor effects were found for imazamox, chlorsulfuron, glufosinate and glyphosate resistance. The importance of the breeding plan and the genetic background on the emergence of these effects is pointed out. Breeders' efforts to produce better varieties could compensate for the yield loss, which eliminates any possibility of formulating generic conclusions on pleiotropic effects that can be applied to all resistant crops.

Comments on the paper "A statistical assessment of differences and equivalences between genetically modified and reference plant varieties" by van der Voet et al. 2011

van der Voet et al. (2011) describe statistical methodology that the European Food Safety Authority expects an applicant to adopt when making a GM crop regulatory submission. Key to their proposed methodology is the inclusion of reference varieties in the experimental design to provide a measure of natural variation amongst commercially grown crops. While taking proper account of natural variation amongst commercial varieties in the safety assessment of GM plants makes good sense, the methodology described by the authors is shown here to be fundamentally flawed and consequently cannot be considered fit for purpose in its current form.

Characterization of the transgenic rice event TT51-1 and construction of a reference plasmid

Transgenic rice TT51-1 (BT63) is an insect resistant strain that was granted for safety certificate in China in 2009. This study characterizes the transgenic event TT51-1 using a GenomeWalker strategy. The organization of the transgenes indicated that the transgenes on two plasmids, pFHBT1 and pGL2RC7, had been integrated at the same locus. The sequence of the event TT51-1 spanned 8725 bp, including a truncated Cry1Ab/Ac cassette, an intact Cry1Ab/Ac cassette, two Amp gene segments, and an Hph gene segment. The 5' and 3' plant flanking sequences were isolated and used to locate the transgenes to chromosome 10 in TT51-1. The isolated TT51-1 fragment and a fragment of the rice PLD gene were integrated into a plasmid vector, to create plasmid pK-TT51 as a calibrator for detecting rice containing TT51-1. Analysis of unknown samples indicated that the reference plasmid was a reliable alternative to TT51-1 genomic DNA.

A statistical assessment of differences and equivalences between genetically modified and reference plant varieties

Background

Safety assessment of genetically modified organisms is currently often performed by comparative evaluation. However, natural variation of plant characteristics between commercial varieties is usually not considered explicitly in the statistical computations underlying the assessment.

Results

Statistical methods are described for the assessment of the difference between a genetically modified (GM) plant variety and a conventional non-GM counterpart, and for the assessment of the equivalence between the GM variety and a group of reference plant varieties which have a history of safe use. It is proposed to present the results of both difference and equivalence testing for all relevant plant characteristics simultaneously in one or a few graphs, as an aid for further interpretation in safety assessment. A procedure is suggested to derive equivalence limits from the observed results for the reference plant varieties using a specific implementation of the linear mixed model. Three different equivalence tests are defined to classify any result in one of four equivalence classes. The performance of the proposed methods is investigated by a simulation study, and the methods are illustrated on compositional data from a field study on maize grain.

Conclusions

A clear distinction of practical relevance is shown between difference and equivalence testing. The proposed tests are shown to have appropriate performance characteristics by simulation, and the proposed simultaneous graphical representation of results was found to be helpful for the interpretation of results from a practical field trial data set.

Assessing the natural variability in crop composition

The number of evaluations of the nutrient composition of food and feed crops has increased over the past 15years due to the introduction of new crops using the tools of modern biotechnology. The composition of these crops has been extensively compared with conventional (non-transgenic) controls as an integral part of the comparative safety assessment process. Following guidelines outlined in the Organization of Economic Co-operation and Development (OECD) Consensus Documents, most of these studies have incorporated field trials at multiple geographies and a diverse range of commercially available varieties/hybrids that are analyzed to understand natural variability in composition due to genetic and environmental influences. Using studies conducted in the US, Argentina and Brazil over multiple growing seasons, this report documents the effect of geography, growing season, and genetic background on soybean composition where fatty acids and isoflavones were shown to be particularly variable. A separate investigation of 96 different maize hybrids grown at three locations in the US demonstrated that levels of free amino acids, sugars/polyols, and molecules associated with stress response can vary to a greater degree than that observed for more abundant components. The International Life Sciences Institute (ILSI) crop composition database has proven to be an important resource for collecting and disseminating nutrient composition data to promote a further understanding of the variability that occurs naturally in crops used for food and feed.

Unintended compositional changes in transgenic rice seeds ( Oryza sativa L.) studied by spectral and chromatographic analysis coupled with chemometrics methods

Unintended compositional changes in transgenic rice seeds were studied by near-infrared reflectance, GC-MS, HPLC, and ICP-AES coupled with chemometrics strategies. Three kinds of transgenic rice with resistance to fungal diseases or insect pests were comparatively studied with the nontransgenic counterparts in terms of key nutrients such as protein, amino acids, fatty acids, vitamins, elements, and antinutrient phytic acid recommended by the Organization for Economic Co-operation and Development (OECD). The compositional profiles were discriminated by chemometrics methods, and the discriminatory compounds were protein, three amino acids, two fatty acids, two vitamins, and several elements. Significance of differences for these compounds was proved by analysis of variance, and the variation extent ranged from 20 to 74% for amino acids, from 19 to 38% for fatty acids, from 25 to 57% for vitamins, from 20 to 50% for elements, and 25% for protein, whereas phytic acid content did not change significantly. The unintended compositional alterations as well as unintended change of physical characteristic in transgenic rice compared with nontransgenic rice might be related to the genetic transformation, the effect of which needs to be elucidated by additional studies.

Safe composition levels of transgenic crops assessed via a clinical medicine model

Substantial equivalence has become established as a foundation concept in the safety evaluation of transgenic crops. In the case of a food and feed crop, no single variety is considered the standard for safety or nutrition, so the substantial equivalence of transgenic crops is investigated relative to the array of commercial crop varieties with a history of safe consumption. Although used extensively in clinical medicine to compare new generic drugs with brand-name drugs, equivalence limits are shown to be a poor model for comparing transgenic crops with an array of reference crop varieties. We suggest an alternate model, also analogous to that used in clinical medicine, where reference intervals are constructed for a healthy heterogeneous population. Specifically, we advocate the use of distribution-free tolerance intervals calculated across a large amount of publicly available compositional data such as is found in the International Life Sciences Institute Crop Composition Database.

The pleiotropic effects of the bar gene and glufosinate on the Arabidopsis transcriptome

The Arabidopsis transcriptome was studied using the Affymetrix Arabidopsis ATH1 GeneChip in wild-type plants and glufosinate-tolerant transgenic plants expressing the bialaphos resistance (bar) gene. Pleiotropic effects were specifically generated in the transcriptomes of transgenic plants by both the bar gene and glufosinate treatments. In the absence of glufosinate, four genes were differentially expressed in the transgenic lines and another 80 genes were differentially expressed in the presence of glufosinate, 29 of which were specific to transgenic plants. In contrast, the number of differentially expressed genes specific to wild-type plants was 194 during the early response at 6 h of glufosinate treatment, and increased to 3711 during the late response at 48 h. Although the wild-type plants undergo extensive transcriptional reprofiling in response to herbicide-induced stress and, finally, plant death, the transgenic plants appear to activate other detoxification processes to offset the toxic effects of the residual herbicide or its derivatives. This study provides the first description of the pleiotropic effects of the bar gene and glufosinate on the plant transcriptome.

The pleiotropic effects of the bar gene and glufosinate on the Arabidopsis transcriptome

The Arabidopsis transcriptome was studied using the Affymetrix Arabidopsis ATH1 GeneChip in wild-type plants and glufosinate-tolerant transgenic plants expressing the bialaphos resistance (bar) gene. Pleiotropic effects were specifically generated in the transcriptomes of transgenic plants by both the bar gene and glufosinate treatments. In the absence of glufosinate, four genes were differentially expressed in the transgenic lines and another 80 genes were differentially expressed in the presence of glufosinate, 29 of which were specific to transgenic plants. In contrast, the number of differentially expressed genes specific to wild-type plants was 194 during the early response at 6 h of glufosinate treatment, and increased to 3711 during the late response at 48 h. Although the wild-type plants undergo extensive transcriptional reprofiling in response to herbicide-induced stress and, finally, plant death, the transgenic plants appear to activate other detoxification processes to offset the toxic effects of the residual herbicide or its derivatives. This study provides the first description of the pleiotropic effects of the bar gene and glufosinate on the plant transcriptome.

Transgenic wheat, barley and oats: production and characterization

Ever since the first developments in plant transformation technology using model plant species in the early 1980s, there has been a body of plant science research devoted to adapting these techniques to the transformation of crop plants. For some crop species progress was relatively rapid, but in other crop groups such as the small grain cereals, which were not readily amenable to culture in vitro and were not natural hosts to Agrobacterium, it has taken nearly two decades to develop reliable and robust transformation methods.In the following chapters of this book, transformation procedures for small grain cereals are presented, together with methods for gene and protein expression and the characterization of transgenic plants. In this introductory chapter we try to put these later chapters into context, giving an overview of the development of transformation technology for small grain cereals, discussing some of the pros and cons of the techniques and what limitations still exist.

Comparison of nutritional quality between Chinese indica rice with sck and cry1Ac genes and its nontransgenic counterpart

Nutritional assessment of transgenic crops used for human food and animal feed is an important aspect of safety evaluations. An insect-resistant rice (IRR) was generated by the stable insertion of sck, a modified cowpea trypsin inhibitor gene, and cry1Ac, encoding a crystal protein from Bacillus thuringiensis into the genome of a common variety of Chinese indica rice. The composition of the brown and milled rice grain from the resulted IRR line designated Liangyou Kefeng No. 6 was compared with that of the parental rice cultivar Liangyou 2186. Nutrients, including the proximates, amino acids, fatty acids, minerals, and vitamins, were measured. The antinutritive components such as phytic acid, lectin, and trypsin inhibitors were also examined. The data demonstrated that the nutritional quality of both the brown and milled rice grains from the transgenic line was substantially equivalent to that of the nontransgenic counterpart, and measured amounts of nutritional components fell within the range of values reported for other commercial lines.

Compositional assessment of event DAS-59122-7 maize using substantial equivalence

Event DAS-59122-7 (Herculex RW) maize (Zea mays L.) plants were transformed to express the Cry34Ab1 and Cry35Ab1 binary insecticidal crystal proteins originally isolated from Bacillus thuringiensis Berliner (Bt) strain PS149B1. These proteins protect maize roots from attack by corn rootworms, Diabrotica spp. DAS-59122-7 maize also contains the pat gene, originally isolated from Streptomyces viridochromogenes, which confers tolerance to glufosinate-ammonium herbicides (e.g. Liberty). We assessed the composition of these transgenic plants (with and without Liberty herbicide treatment), grown at a total of eight fields sites over 2 years, by applying the principle of substantial equivalence. Forage and grain samples were analyzed for proximates, fiber and minerals, and grain was further analyzed for amino acids, fatty acids, vitamins, secondary metabolites and anti-nutrients. Data plots were prepared that allow for efficient investigation of equivalency between event DAS-59122-7 maize and a non-transgenic near-isogenic maize line grown contemporaneously. Results demonstrated that DAS-59122-7 maize is equivalent to non-transgenic maize with respect to these important constituents.

A metabolomic study of substantial equivalence of field-grown genetically modified wheat

The 'substantial equivalence' of three transgenic wheats expressing additional high-molecular-weight subunit genes and the corresponding parental lines (two lines plus a null transformant) was examined using metabolite profiling of samples grown in replicate field trials on two UK sites (Rothamsted, Hertfordshire and Long Ashton, near Bristol) for 3 years. Multivariate comparison of the proton nuclear magnetic resonance spectra of polar metabolites extracted with deuterated methanol-water showed a stronger influence of site and year than of genotype. Nevertheless, some separation between the transgenic and parental lines was observed, notably between the transgenic line B73-6-1 (which had the highest level of transgene expression) and its parental line L88-6. Comparison of the spectra showed that this separation resulted from increased levels of maltose and/or sucrose in this transgenic line, and that differences in free amino acids were also apparent. More detailed studies of the amino acid composition of material grown in 2000 were carried out using gas chromatography-mass spectrometry. The most noticeable difference was that the samples grown at Rothamsted consistently contained larger amounts of acidic amino acids (glutamic, aspartic) and their amides (glutamine, asparagine). In addition, the related lines, L88-6 and B73-6-1, both contained larger amounts of proline and gamma-aminobutyric acid when grown at Long Ashton than at Rothamsted. The results clearly demonstrate that the environment affects the metabolome and that any differences between the control and transgenic lines are generally within the same range as the differences observed between the control lines grown on different sites and in different years.