William P. Ridley

Natural variation in crop composition and the impact of transgenesis

volume 28 number 5 mAY 2010 nature biotechnology These, and other studies (e.g., refs. 3–5), have also suggested a high degree of natural variability inherent to crop biochemical and metabolite composition. It is therefore reasonable to ask if changes in composition associated with modern transgenic breeding practices are different in scope from those attributable to natural genotypic and environmentally mediated variation. We reasoned that a systematic analysis encompassing published compositional data generated under OECD guidelines on several GM products grown in a range of geographies, under different regional agronomic practices and over multiple seasons would provide an effective overview of the relative impacts of transgenesis-derived agronomic traits with natural variation on crop composition. GM corn and GM soybean now represent 30.0% and 53%, respectively, of global production6. Our analysis therefore evaluated compositional data reported on grain and seed harvested from different GM corn and GM soybean products as these now represent a significant percentage of global production of these crops as well as provide an abundance of compositional data from diverse climates and growing regions. The high-quality compositional data generated according to principles outlined in the Organization for Economic Cooperation and Development (OECD; Paris) consensus documents2 are available. On a product-byproduct basis, compositional equivalence of GM crops and their conventional comparators has been demonstrated in potato, cotton, soybean, corn, rice, wheat and alfalfa (for a list of references describing compositional and omics comparisons of GM and non-GM comparators, see Supplementary References). In addition to the compositional studies conducted within regulatory programs, biochemical studies on GM crops have been extensively pursued by public and private research sectors. Although there are complexities in the interpretation of modern profiling technologies, and no standardized framework for comparisons, the lack of variation between GM crops and their conventional comparators at the transcriptomic, proteomic and metabolomic level has been independently corroborated. These profiling evaluations extend to a wide range of plants including wheat, potato, soybean, rice, tomato, tobacco, Arabidopsis and Gerbera (see Supplementary References). To the Editor: Compositional equivalence of crops improved through biotech-derived transgenic, or genetically modified (GM), traits and their conventional (non-GM) comparators is an important criterion in breeding as well as a key aspect of risk assessments of commercial candidates. We present here an analysis evaluated from compositional data on GM corn and GM soybean varieties grown across a range of geographies and growing seasons with the aim of not only assessing the relative impact of transgene insertion on compositional variation in comparison with the effect of environmental factors but also reviewing the implications of these results on the safety assessment process. Specifically, our analysis includes evaluation of seven GM crop varieties from a total of nine countries and eleven growing seasons. On the basis of our data, we conclude that compositional differences between GM varieties and their conventional comparators were encompassed within the natural variability of the conventional crop and that the composition of GM and conventional crops cannot be disaggregated. Plant breeding programs expect to either maintain compositional quality during enhancement of other agronomic traits or improve crop compositional quality through intended changes in the levels of key nutrients or antinutrients. Over the past two decades, one of the most successful approaches to enhancing agronomic traits in crops is the insertion of trait-encoding genes using the techniques of modern biotech. Compositional equivalence between GM crops and conventional (non-GM) comparators is an important breeding goal but is also often considered to provide an “equal or increased assurance of the safety of foods derived from genetically modified plants”1. Comparative compositional studies are therefore included as a significant component of risk assessments of new GM crops. As a consequence, a large body of Natural variation in crop composition and the impact of transgenesis

Composition of Forage and Grain from Second-Generation Insect-Protected Corn MON 89034 Is Equivalent to That of Conventional Corn (Zea mays L.)

Insect-protected corn hybrids containing Cry insecticidal proteins derived from Bacillus thuringiensis have protection from target pests and provide effective management of insect resistance. MON 89034 hybrids have been developed that produce both the Cry1A.105 and Cry2Ab2 proteins, which provide two independent modes of insecticidal action against the European corn borer ( Ostrinia nubilalis ) and other lepidopteran insect pests of corn. The composition of MON 89034 corn was compared to conventional corn by measuring proximates, fiber, and minerals in forage and by measuring proximates, fiber, amino acids, fatty acids, vitamins, minerals, antinutrients, and secondary metabolites in grain collected from 10 replicated field sites across the United States and Argentina during the 2004-2005 growing seasons. Analyses established that the forage and grain from MON 89034 are compositionally comparable to the control corn hybrid and conventional corn reference hybrids. These findings support the conclusion that MON 89034 is compositionally equivalent to conventional corn hybrids.

Composition of Grain, Forage, and Processed Fractions from Second-Generation Glyphosate-Tolerant Soybean, MON 89788, Is Equivalent to That of Conventional Soybean (Glycine max L.)

Developments in biotechnology and molecular-assisted breeding have led to the development of a second-generation glyphosate-tolerant soybean product, MON 89788. The MON 89788 event was produced by direct transformation of a cp4 epsps (5-enolpyruvylshikimate-3-phosphate synthase) gene cassette derived from Agrobacterium sp. strain CP4 into an elite soybean germplasm known for its superior agronomic characteristics and high yielding property. The purpose of this work was to assess whether the nutrient and antinutrient levels in seed and forage tissues of MON 89788 are comparable to those in the conventional soybean variety, A3244, which has background genetics similar to MON 89788 but does not contain the cp4 epsps gene cassette. Additional conventional soybean varieties currently in the marketplace were also included in the analysis to establish a range of natural variability for each analyte, where the range of variability is defined by a 99% tolerance interval for that particular analyte. Compositional analyses were conducted on forage, seed and four processed fractions from soybeans grown in ten sites across both the United States and Argentina during the 2004-2005 growing seasons. Forage samples were analyzed for levels of proximates (ash, fat, moisture, and protein) and fiber. Seed samples were analyzed for proximates, fiber, antinutrients, and vitamin E. Defatted, toasted (DT) meal was analyzed for proximates, fiber, amino acids, and antinutrients. Refined, bleached, and deodorized (RBD) oil was analyzed for fatty acids and vitamin E. Protein isolate was analyzed for amino acids and moisture. Crude Lecithin was analyzed for phosphatides. Results of the comparisons indicate that MON 89788 is compositionally and nutritionally equivalent to conventional soybean varieties currently in commerce.

Compositions of Forage and Seed from Second-Generation Glyphosate-Tolerant Soybean MON 89788 and Insect-Protected Soybean MON 87701 from Brazil Are Equivalent to Those of Conventional Soybean (Glycine max)

Brazil has become one of the largest soybean producers. Two Monsanto Co. biotechnology-derived soybean products are designed to offer benefits in weed and pest management. These are second-generation glyphosate-tolerant soybean, MON 89788, and insect-protected soybean, MON 87701. The second-generation glyphosate-tolerant soybean product, MON 89788, contains the 5-enolpyruvylshikimate-3-phosphate synthase gene derived from Agrobacterium sp. strain CP4 (cp4 epsps). MON 87701 contains the cry1Ac gene and expression of the Cry1Ac protein providing protection from feeding damage caused by certain lepidopteran insect pests. The purpose of this assessment was to determine whether the compositions of seed and forage of MON 89788 and MON 87701 are comparable to those of conventional soybean grown in two geographically and climatically distinct regions in multiple replicated sites in Brazil during the 2007-2008 growing season. Overall, results demonstrated that the seed and forage of MON 89788 and MON 87701 are compositionally equivalent to those of conventional soybean. Strikingly, the results also showed that differences in mean component values of forage and seed from the two controls grown in the different geographical regions were generally greater than that observed in test and control comparisons. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) of compositional data generated on MON 89788, MON 87701, and their respective region-specific controls provide a graphical illustration of how natural variation contributes more than biotechnology-driven genetic modification to compositional variability in soybean. Levels of isoflavones and fatty acids were particularly variable.

Compositions of Seed, Forage, and Processed Fractions from Insect-Protected Soybean MON 87701 Are Equivalent to Those of Conventional Soybean

Monsanto Co. has developed biotechnology-derived, insect-protected soybean MON 87701 that produces the Cry1Ac insecticidal crystal (delta-endotoxin) protein derived from Bacillus thuringiensis (Bt) subsp. kurstaki. Cry1Ac provides protection from feeding damage caused by certain targeted lepidopteran pests. The purpose of this work was to assess whether the compositions of seed, forage, and processed fractions (meal, oil, protein isolate, and lecithin) of MON 87701 are comparable to those of conventional soybean. Compositional analyses were conducted on seed and forage tissues harvested from MON 87701 and conventional soybean grown in multiple replicated sites in the United States during the 2007 growing season and in Argentina during the 2007-2008 growing season. Seed, forage, and processed fractions from conventional soybean varieties currently in the marketplace were included in the analyses to establish a range of natural variability for each compositional component; the range of variability was defined by a 99% tolerance interval. Additional seed was collected from soybean grown in a separate U.S. production during the 2007 season. This seed and processed fractions (meal, oil, protein isolate, and crude lecithin) derived from it were also subjected to compositional analyses. Forage samples were analyzed for levels of proximates (ash, fat, moisture, and protein), carbohydrates by calculation, and fiber. Seed samples were analyzed for proximates, carbohydrates by calculation, fiber, amino acids, fatty acids, antinutrients, and vitamin E. Toasted, defatted (TD) meal was analyzed for proximates, fiber, amino acids, and antinutrients. Refined, bleached, and deodorized (RBD) oil was analyzed for fatty acids and vitamin E. Protein isolate was analyzed for amino acids and moisture. Crude lecithin was analyzed for phosphatides. Overall, results demonstrated that the seed, forage, and processed fractions of MON 87701 are compositionally equivalent to those of conventional soybean.

The forage and grain of MON 87460, a drought-tolerant corn hybrid, are compositionally equivalent to that of conventional corn.

MON 87460 contains a gene that expresses cold shock protein B (CSPB) from Bacillus subtilis. Expression of this gene confers a yield advantage when yield is limited by water availability. Compositional analyses of MON 87460 and a conventional corn variety with similar background genetics were conducted on forage and grain harvested from multiple replicated field sites across the United States during the 2006 growing season and across Chile during the 2006-2007 growing season. The U.S. field trials were conducted under typical agronomic practices, whereas the Chilean field trials incorporated a strip-plot design that included well-watered and water-limited treatments. Results demonstrated that levels of the components analyzed were comparable between MON 87460, the conventional control, and the commercially available corn hybrids.

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.

Evaluation of compositional equivalence for multitrait biotechnology crops.

Compositional analysis is an important tool in the evaluation of the safety and nutritional status of biotechnology-derived crops. As part of the comparative assessment of a biotechnology-derived crop, its composition is evaluated by quantitative measurement of the levels of key nutrients, antinutrients, and secondary metabolites and compared to that of conventional crops. To evaluate the effect of combining multiple biotech traits through conventional breeding, the forage and grain compositions of the double combinations MON 810 × NK603, MON 863 × MON 810, and MON 863 × NK603 and the triple combination MON 863 × NK603 × MON 810 were compared to their respective near-isogenic, conventional control hybrids. Overall, a total of 241 statistical comparisons between the multitrait biotechnology crop and its corresponding conventional controls were conducted. Of these comparisons 192 (79.7%) were not statistically significantly different (p > 0.05), and all 49 of the differences were within the 99% tolerance interval for commercial hybrids grown in the same field or related field trials. These data on combined trait biotechnology-derived products demonstrated that the forage and grain were compositionally equivalent to their conventional comparators, indicating the absence of any influence of combining insect protection and herbicide tolerance traits by conventional breeding on compositional variation.

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.