Stacked Genetically Engineered Trait Products Produced by

Jun 28, 2018 - ACS AuthorChoice - This is an open access article published under an ... using conventional breeding to produce a stacked trait product...
1 downloads 0 Views 452KB Size
Subscriber access provided by Kaohsiung Medical University

Food Safety and Toxicology

Stacked GE trait products produced by conventional breeding reflect the compositional profiles of their component single trait products Erin Bell, Shuichi Nakai, and Luis Burzio J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.8b02317 • Publication Date (Web): 28 Jun 2018 Downloaded from http://pubs.acs.org on July 3, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 33

Journal of Agricultural and Food Chemistry

1 2 3

Stacked GE trait products produced by conventional breeding reflect the compositional profiles of their component single trait products

4 5 6

Erin Bell*1, Shuichi Nakai2, and Luis A. Burzio1

7 8

*To whom correspondence should be addressed. Email: [email protected]

9 10

1

Monsanto Company, 700 Chesterfield Parkway West, Chesterfield, MO 63017, U.S.A.

11

2

Monsanto Japan Limited, 2-5-18 Kyobashi, Chuo-ku, Tokyo 104-0031, Japan.

12 13

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

14

Abstract

15

An expanding trend for genetically engineered crops is to cultivate varieties in which two or

16

more single trait products have been combined using conventional breeding to produce a

17

stacked trait product that provides a useful grouping of traits. Here we report results from

18

compositional analysis of several GE stacked trait products from maize and soybean. The

19

results demonstrate that these products are each compositionally equivalent to a relevant non-

20

GE comparator variety, except for predictable shifts in the fatty acid profile in the case of

21

stacked trait products that contain a trait, MON 87705, that confers a high-oleic acid phenotype

22

in soybean. In each case, the conclusion on compositional equivalence for the stacked trait

23

product reflects the conclusions obtained for the single trait products. These results provide

24

strong support for conducting a reassessment of those regulatory guidelines that mandate

25

explicit characterization of stacked trait products produced through conventional breeding.

26 27 28

Key words: composition; stacked trait product; genetically engineered crops; conventional

29

breeding

30

ACS Paragon Plus Environment

Page 2 of 33

Page 3 of 33

Journal of Agricultural and Food Chemistry

31

Introduction

32

Humans have been noticing and selecting for useful plant features since the beginning of

33

agriculture, from the initial domestication of wild species to the incremental improvements of

34

cultivated species. For example, the propagation of a variant with characteristics of reduced

35

seed shattering was important for the domestication of rice, and selection of other useful

36

features over time contributed to rice’s advancement as a primary food source for a large

37

portion of the world population (1, 2). This process of selecting for desirable characteristics has

38

continued, and, using more sophisticated tools, is still the basis of modern plant breeding. A

39

key goal of plant breeding is to develop varieties that combine many useful characteristics, to

40

increase the utility and value for farmers and/or consumers. Plant breeding has an established

41

history of safety (3), in that thousands of new varieties have been introduced into food and/or

42

feed use without the emergence of safety concerns (4).

43

The introduction of desirable characteristics can also be achieved using the tools of

44

biotechnology. Genetically engineered (GE; also referred to as GM) plants are developed

45

through plant transformation to achieve the targeted introduction of a desirable characteristic,

46

or “trait”, that may not be obtainable through traditional plant breeding processes. When GE

47

techniques were first used for the introduction of desired traits into crops, intergovernmental

48

organizations and many governments established regulatory frameworks for pre-market

49

assessments of the food/feed safety of new GE plants (5), such that each new GE crop is

50

subjected to review by one or more regulatory authorities prior to release for commercial use.

51

For example, since the commercialization of the first GE crop in the U.S. in 1992, there have

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

52

been 126 GE crop products deregulated for cultivation in the United States (6) following

53

regulatory evaluation of prescribed safety assessment approaches (7).

54

The utility of a crop variety can be increased by breeding to combine two or more desired

55

characteristics found in parental lines. For example, conventional1 plant breeding practices,

56

including backcrossing, phenotypic selection, and marker-assisted selection, were used to

57

introduce the native characteristic of bacterial blight resistance from one rice variety into a

58

Basmati rice variety, resulting in a variety that displayed both bacterial blight resistance and

59

Basmati quality characteristics (8). GE traits can also be combined by conventional breeding;

60

such combined trait products are likewise developed to provide growers and/or consumers

61

with more benefits in a single plant, for example traits to address the agronomic challenges of

62

weeds and insect pests simultaneously.

63

To produce a GE crop that addresses an agricultural challenge or provides a product with

64

consumer benefit, developers typically use plant transformation to generate many independent

65

lines containing the trait of interest, which are then extensively characterized and screened to

66

select one that will be advanced for commercial use (9). The resulting trait-containing product

67

(referred to here as a “single trait product” or “GE single”) is designated with a unique identifier

68

(for example, MON 89788, a GE soybean that is tolerant to the herbicide glyphosate). A crop

69

that contains the traits from two or more GE singles, that have been combined using

70

conventional breeding, is referred to here as a “stacked trait product” (or “stack”).

71

Designations for stacked trait products are differentiated from GE single trait products, typically

72

through a naming convention that combines the names of each component GE single using the 1

“Conventional” breeding refers here to plant breeding techniques excluding GE.

ACS Paragon Plus Environment

Page 4 of 33

Page 5 of 33

Journal of Agricultural and Food Chemistry

73

“ד nomenclature typical for breeding crosses, for example MON 87705 × MON 89788 (a

74

soybean stacked trait product with an improved fatty acid profile and glyphosate tolerance).

75

Over the past 10-15 years there has been a notable increase in the number of stacked trait

76

products developed and released, including those that contain three or more GE singles (10).

77

The evaluation of a GE single trait product follows guidelines that have been established by

78

Codex Alimentarius (5) as relevant and sufficient for food safety assessment of GE varieties.

79

From a regulatory perspective, stacked trait products often differ in a key way from GE single

80

trait products in that they contain traits that are not new to regulatory authorities, having

81

already been fully evaluated in the component GE singles. Given that the safety concerns

82

raised about GE crops revolve around the safety of the introduced trait and the potential for

83

adverse unintended effects due to trait introduction, this distinction is important. Here we

84

report the conclusions from compositional assessment of several GE stacked trait products,

85

conducted by comparison of component values between the GE varieties and closely related

86

non-GE comparators. The results indicate that a conclusion of compositional equivalence for a

87

GE stacked trait product relative to its comparator aligns with compositional equivalence

88

conclusions for the relevant GE single trait products. These results provide empirical support

89

for a regulatory model in which explicit risk assessment of a GE stacked trait product is

90

mandated only in limited circumstances (4).

91

Materials and Methods

92

Maize or soybean plants were cultivated in replicated field trials in the region and year(s) as

93

indicated below and/or as cited. In each case, a closely related non-GE variety, indicated as

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

94

“control” in Tables 2 and 3, was grown concurrently with the indicated GE (“test”) varieties,

95

with each as entries in a randomized complete block design in the same field trial. In cases

96

where the GE variety was treated as indicated with one or more trait-relevant herbicides, the

97

treatment was applied to reflect conditions that could be typical of commercial cultivation for

98

that crop. Information regarding the trait characteristics corresponding to the GE single trait

99

products is provided in Table 1.

100

Specific field trials:

101



The maize products MON 87427 and MON 87427 x MON 89034 x MON 88017 were grown

102

in the United States in 2008, at three locations (one each in Arkansas, Illinois, and Iowa),

103

with three replications per location. Test plants were treated with glyphosate herbicide.

104



The maize product MON 89034 × TC1507 × MON 88017 × DAS-59122-7 was grown in the

105

United States in2008, at four locations (one each in Illinois, Indiana, Iowa, and Nebraska),

106

with three replications per location.

107

glufosinate herbicides.

108



Test plants were treated with glyphosate and

The maize product MON 87427 × MON 89034 × TC1507 × MON 88017 × DAS-59122-7 was

109

grown in the United States in 2010, at eight locations (one each in Arkansas, Indiana,

110

Kansas and Nebraska, and two each in Illinois and Iowa), with four replications per location.

111

Test plants were treated with glyphosate and glufosinate herbicides.

112



The soybean product MON 87705 was grown in Chile during the 2007/2008 season, at five

113

locations (one each in the provinces of Cachapoal, Chacabuco, Colchagua, Maipo, and

114

Melipilla), with three replications per location.

ACS Paragon Plus Environment

Page 6 of 33

Page 7 of 33

115

Journal of Agricultural and Food Chemistry



The soybean product MON 87705 x MON 89788 was grown in the United States in 2009 at

116

eight locations (one each in Iowa, Indiana, Kansas, Missouri, and Nebraska, and three in

117

Illinois), with four replications per location. Test plants were treated with glyphosate

118

herbicide.

119



The soybean product MON 87705 x MON 87708 x MON 89788 was grown in Argentina

120

during the 2013/2014 season, at five locations (four in Buenos Aires province and one in

121

Santa Fe province), with four replications per location. Test plants were treated with

122

glyphosate and dicamba herbicides.

123 124

Key nutrients and anti-nutrients were analyzed from harvested maize grain and harvested

125

soybean seed. Validated analytical methods, consistent with those described in (11), (12), or

126

(13), were used to assess analyte levels. Resulting data were combined by entry across all

127

replicates and locations within a study, and combined site mean values for each component

128

were calculated. For each component within each study, the combined site mean values for

129

the test substance and the control substance were statistically compared using a mixed model

130

analysis of variance, as described in Drury et al. (11). Statistical significance was defined at the

131

level of p < 0.05.

132 133

Results and Discussion

134

Assessment of stacked trait products from maize and soybean confirm the compositional

135

equivalence of these products to conventional crop varieties

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

136

Whereas conventionally-bred crops are presumed to be safe, GE single trait products undergo

137

an explicit comparative compositional assessment of important nutrients and relevant toxicants

138

to evaluate the substantial equivalence of the GE crop product to non-GE varieties (14). Since

139

its inception, the core objective of compositional assessment of a GE crop product has been to

140

evaluate whether the composition of the GE product is as safe as that of conventional varieties

141

of the same crop (15). It is known that both genetic factors (such as crop variety) and

142

environmental factors (growing location, weather conditions, application of fertilizer, etc.) can

143

impact the composition of a crop, and that the level of a particular component can vary

144

substantially without posing a nutritional or safety concern (16, 17). This natural variability

145

provides important context, in that a value for a component in a GE product that is consistent

146

with previously-observed values for non-GE varieties provides assurance that the GE crop is as

147

safe as conventional varieties with respect to the level of that given component. It is important

148

to note that values outside of documented variation would not automatically indicate lack of

149

safety.

150

Monsanto Company has developed several stacked trait products that contain three or more

151

single traits. Compositional data for two recently developed stacked trait products, MON

152

87427 x MON 89034 × TC1507 × MON 88017 × DAS-59122-7 from maize, and MON 87705 x

153

MON 89788 x MON 89788 from soybean, are reported here. A summary of the single trait

154

products included in the maize or soybean stacked trait products is provided in Table 1.

155

Table 2 presents composition data for the stacked trait product MON 87427 x MON 89034 ×

156

TC1507 × MON 88017 × DAS-59122-7 from maize. For comparison purposes, data from related

157

“lower order” stacked trait products, that contain a subset of the traits combined in the highest

ACS Paragon Plus Environment

Page 8 of 33

Page 9 of 33

Journal of Agricultural and Food Chemistry

158

order stacked trait product, as well from selected single trait products, are also provided. For

159

each GE crop, values were statistically compared to those from a closely-related, concurrently-

160

grown non-GE, or “conventional”, variety; data for these comparators are also shown. As

161

shown in Table 2, individual values for any given component could vary from analysis to analysis.

162

Figure 1A represents one example of this, showing the range of maize grain protein values for

163

each GE product and its conventional comparator.

164

differences between the GE product and a relevant conventional comparator were observed,

165

they represented a small difference in the level of the particular component. For example, the

166

statistically significant difference in mean protein level in MON 87427 × MON 89034 × TC1507 ×

167

MON 88017 × DAS-59122-7 represented a less than 10 % difference relative to the conventional

168

comparator. In addition, the values for both the trait-containing variety and the conventional

169

comparator were within the range of characterized natural variability for the crop, as defined

170

by the International Life Sciences Institute Crop Composition Database (ILSI CCDB) ranges (Table

171

2; Figure 1A). The ILSI CCDB, which includes data from the evaluation of conventional crop

172

samples using validated analytical methods, provides a robust compilation of high quality non-

173

GE composition data for several crops (18); these data provide valuable context for any

174

statistical differences. Thus, despite variation in component levels, the conclusion for each of

175

these products was that the neither the introduced trait(s), nor the process of developing the

176

GE product, was a meaningful contributor to compositional variability, and that the product

177

was compositionally equivalent to commercially available conventional maize varieties. [Table

178

S1 presents additional component data for several of these maize products.]

While some statistically significant

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

179

Table 3 presents composition data for the soybean stacked trait product MON 87705 x MON

180

87708 x MON 89788, as well as data from some related GE single and stacked trait products. Of

181

note is that one of the GE single trait products shown, MON 87705, was developed to confer a

182

modified fatty acid profile, including an increase in oleic acid (19). These summarized data

183

indicate that the modified fatty acid profile trait from MON 87705 functioned as intended when

184

combined with the other GE singles in the stacked trait products, and that otherwise the traits

185

assessed were not meaningful contributors to compositional variability. Figure 1B, which

186

shows ranges of protein values in these soybean varieties, provides a graphic representation of

187

the compositional equivalence of protein levels for each GE variety with its conventional

188

comparator. [Table S2 reports additional component data for some of these soybean products.]

189

In Table 2, MON 87427 × MON 89034 × TC1507 × MON 88017 × DAS-59122-7 (generically, A × B

190

× C × D × E) represents a higher order stacked trait product, and MON 87427 × MON 89034 ×

191

MON 88017 (generically, A × B × D) represents a lower order stacked trait product. The

192

commercialization of both higher order and lower order stacked trait products provides

193

flexibility, allowing farmers to choose the combination of traits that are most useful for their

194

cultivation conditions. As explicitly shown here for the high oleic acid phenotype for MON

195

87705, the intended compositional differences in fatty acid levels manifested themselves as

196

expected in stacks of varying orders, with both of the GE stacked trait products that include

197

MON 87705 having an altered fatty acid profile relative to their respective control (see Table 3).

198

In a hypothetical situation where a combination of traits from two previously evaluated and

199

approved GE singles (e.g. traits F and G) resulted in a unique characteristic for the GE breeding

200

stack, it is reasonable to expect that any stacked trait product that included that combination

ACS Paragon Plus Environment

Page 10 of 33

Page 11 of 33

Journal of Agricultural and Food Chemistry

201

would also manifest its unique characteristic, whether a higher order, such as A x B x C x F x G,

202

or a lower order stack, such as A x F x G, or F x G itself. Thus, the hypothetical unique

203

characteristic conferred by the F x G combination could be adequately assessed in the context

204

of safety in any one of the stacked trait products that contained the F × G combination. This

205

suggests that, in cases where compositional assessment of stacked trait products is mandated,

206

evaluation of a higher order stacked trait product would suffice to provide information

207

regarding lower order stacked trait products as well.

208 209

Historic data also demonstrate a lack of compositional impact due to trait stacking

210

Kok et al (20) summarized the outcomes for 22 stacked trait products that had been assessed

211

(including compositional assessment) by the European Food Safety Authority. They concluded

212

that there was no evidence that stacking GE traits through conventional breeding resulted in

213

changes that would raise safety concerns. In addition, several publications have reported the

214

consistency of compositional characteristics of a given stacked trait product with those of a

215

conventional comparator (Table S3). Those reports, considered along with the regulatory

216

approvals of more than 60 stacked trait products (10), provide empirical evidence that, as

217

expected, notable unintended effects arising from the combination of traits in a stacked trait

218

product have not been observed.

219

Risk assessment approaches for stacked trait products vary globally

220

There are regulatory agencies that approach a stacked trait product as a unique GE crop that

221

requires de novo assessment, despite their previously established safety conclusions for the

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

222

individual GE singles and the safety of conventional breeding. One motivation for this approach

223

could be a concern about possible interaction between traits that might lead to plant

224

characteristics that are different from the expected sum of the combined traits. The overall

225

potential for trait interactions in stacked trait products was extensively reviewed in a recent

226

publication (4). The authors highlighted the fact that because the functional characteristics of

227

introduced GE traits are known, it is possible to develop hypotheses on whether a specific

228

combination of traits would interact to affect plant metabolism in a novel way, and on whether

229

the hypothetical interaction would pose any risk. For example, many commercial stacked trait

230

products combine herbicide tolerant (HT) traits. One widely available HT trait is tolerance to

231

glyphosate, an herbicide that inhibits the plant’s 5-enolpyruvylshikimate-3-phosphate synthase

232

(EPSPS) enzyme, that participates in the biosynthesis of aromatic amino acids. Tolerance to

233

glyphosate can be achieved by the introduction of a gene encoding a glyphosate-tolerant EPSPS

234

enzyme. Another HT trait is tolerance to the herbicide dicamba. Tolerance to dicamba can be

235

achieved by introducing a gene encoding dicamba monooxygenase, an enzyme that catalyzes

236

the demethylation of dicamba to a non-herbicidal form. In some stacked trait products,

237

glyphosate tolerance has been combined with dicamba tolerance through conventional

238

breeding. Given the distinct mechanisms by which these two enzymes confer their respective

239

HT trait, and the chemical dissimilarity of their respective substrates, there is no plausible

240

hypothesis that they would interact in a stacked trait product to warrant any novel safety

241

concerns by their combination. For this example, the compositional safety of a GE stacked trait

242

product that confers tolerance to glyphosate and dicamba has also been empirically

243

demonstrated (21).

Specifically for the GE stacked trait products presented here, the maize

ACS Paragon Plus Environment

Page 12 of 33

Page 13 of 33

Journal of Agricultural and Food Chemistry

244

products contain insect resistance and HT traits; similar to the example described, there is no

245

plausible hypothesis for their combined presence to affect the metabolism of the plant and lead

246

to compositional differences. For the soybean products, that contain one or more HT traits and

247

a trait that impacts the fatty acid profile, there is also no plausible hypothesis for trait

248

interaction to affect the metabolism of the plant. As expected, the compositional profiles

249

observed for these GE stacked trait products are consistent with those that would be predicted

250

based on the characteristics of the relevant GE single trait products.

251

et al. concluded that if no plausible hypothesis for an interaction of concern can be developed,

252

further assessment of the stacked trait product is not scientifically justified, based on the

253

previously-determined safety of the constituent GE single trait products and the established

254

safety of conventional breeding (4).

255

Another factor that may motivate assessment of GE breeding stacks is concern regarding a

256

potential for the GE trait combination to affect the stability of one or more of the transgenes

257

(22). As part of the characterization process for each GE single trait product, the stability and

258

inheritance pattern of the inserted transgene is explicitly demonstrated over multiple

259

generations. Once a gene for a given trait is stably integrated into the genome, it behaves like

260

the thousands of other genes in the plant’s genome. While there is a potential for genetic

261

change in all plants and in all breeding processes, two recent publications (20, 23) have

262

concluded that the process of combining traits in a GE breeding stack does not pose unique risk

263

relative to any other conventional breeding process. Thus, this concern does not justify safety

264

assessment of a stacked trait product.

ACS Paragon Plus Environment

More generally, Steiner

Journal of Agricultural and Food Chemistry

265

In considering the global landscape of GE regulations, there are currently three general

266

approaches to the food and feed safety assessment for a stacked trait product:

267

Approach 1. As a product of a conventional breeding process, the stacked trait product is

268

not explicitly assessed

269

Under this approach, no data are required for a stacked trait product generated by

270

conventional breeding of risk-assessed GE single trait products. For some regulatory

271

agencies, the potential for interaction of a new trait with previously approved traits is

272

proactively considered at the time when a new GE single trait product is evaluated.

273

Regulatory agencies may require a written notification regarding the stacked trait

274

product to be commercialized. Examples of agencies that follow this approach are

275

United States Department of Agriculture, United States Food and Drug Administration,

276

Canadian Food Inspection Agency, Health Canada, and Food Standards Australia New

277

Zealand.

278

Approach 2. The requirement for GE breeding stack assessment is determined by the

279

characteristics of the traits being combined

280

Under this approach, stacked trait products that combine certain previously-assessed

281

traits are exempted from safety assessment, while combinations involving other traits

282

(or trait categories) require additional characterization. For example, for Japan’s Food

283

Safety Commission and Ministry of Agriculture, Forestry and Fisheries Feed division, no

284

data are required if the stack combines traits that do not alter metabolism of the host

285

plant (Category 1), such as common herbicide tolerance or insect resistance traits (24).

ACS Paragon Plus Environment

Page 14 of 33

Page 15 of 33

Journal of Agricultural and Food Chemistry

286

For other trait categories (Category 2 or Category 3, that impact plant metabolism or

287

produce new substances, respectively), at least some direct characterization is required,

288

with the scope of the assessment dependent on the nature of the traits being combined.

289

It is interesting to note that this differential approach to stacked trait product safety

290

assessment is relatively new for regulatory agencies in Japan. The decision to no longer

291

require characterization data for stacks combining Category 1 traits was based on

292

scientific considerations and evaluation of the agencies’ historical experience from

293

evaluating many stack combinations without any evidence for safety concerns regarding

294

the stacked trait products. (24)

295

Approach 3.

An explicit safety evaluation is required for any stacked trait product,

296

regardless of the nature of the traits combined

297

Under this approach, at least a subset of the data types previously generated and

298

evaluated for the GE single trait products, such as molecular characterization, protein

299

expression and compositional data, must be also generated and evaluated for a stacked

300

trait product (the exact nature of the data required for the assessment varies by agency).

301

Examples of some regulatory agencies that follow this approach are European Food

302

Safety Authority, Republic of Korea’s Ministry of Food and Drug Safety, Taiwan Food and

303

Drug Administration, and Mexico’s Federal Commission for the Protection Against

304

Sanitary Risk.

305

For stacked trait products, the formulation and evaluation of a product-specific risk hypothesis,

306

that evaluates the need, or lack thereof, for additional explicit safety assessment of a particular

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

307

stacked trait product, represents a rational, scientifically supportable, risk assessment approach

308

(3, 4, 25). However, as noted above, there are regulatory agencies that require explicit

309

characterization and safety assessments for every stacked trait product, independent of a risk

310

hypothesis. Overall, considering 1) the availability of safety conclusions for the relevant single

311

trait products, 2) the safe history of conventional breeding, and 3) the expanding body of

312

empirical data confirming the safety of GE trait stacking through conventional breeding, there is

313

a valid scientific justification to eliminate mandatory requirements to submit and evaluate

314

characterization data for each new stacked trait product. If, in practical terms, a step-wise

315

approach toward the elimination of generic data requirements for stacked trait products is

316

more realistic, refining the focus to a single targeted analysis of the stack could be the first step.

317

Such an approach would provide an empirical bridge to the previous assessments completed

318

for the component GE singles. For example, a streamlined assessment of the stack that focused

319

on composition, evaluating the levels of grain proximates and anti-nutrients in the context of

320

known natural variability, could be used to complement the safety conclusions previously

321

reached for the constituent single trait products.

322

In summary, based on the biological processes underlying conventional breeding and GE

323

breeding stacks, supported by the empirical assessment of more than 60 stacked trait products

324

(10) that show outcomes consistent with the expected impact of these processes, risk

325

assessment principles do not support a need for regulatory-focused characterization and

326

assessment of stacked trait products of previously assessed GE singles, except in cases

327

(currently unprecedented) where a plausible hypothesis of a trait interaction that could impact

328

product safety can be formulated.

Stacked trait products that provide useful GE trait

ACS Paragon Plus Environment

Page 16 of 33

Page 17 of 33

Journal of Agricultural and Food Chemistry

329

combinations are a fast-growing segment of the GE portfolio; for that reason, it is important to

330

appropriately align their regulatory review with the principles of risk assessment.

331

requirement for pre-market evaluations that are not justified under these principles

332

contributes to a high barrier to development, may strain the resources of regulatory agencies

333

tasked with evaluating food and feed safety, and may preclude the use of GE by both public

334

and private developers interested in providing innovative new trait combinations to support

335

agricultural developments that help feed the world’s expanding population.

336 337 338

Abbreviations used

339

GE – genetically engineered

340

ILSI-CCDB – International Life Sciences Institute Crop Composition Database

341

HT – herbicide tolerant

342

EPSPS - 5-enolpyruvylshikimate-3-phosphate synthase

343

DMO – dicamba monooxygenase

344 345

Acknowledgements

346

The authors acknowledge Kevin Glenn for his critical review of the manuscript, and Tim

347

Klusmeyer and Mary Taylor for their assistance in preparing data tables.

ACS Paragon Plus Environment

A

Journal of Agricultural and Food Chemistry

348

Supporting Information

349

Data for additional compositional components for maize are reported in Table S1, and for

350

soybean are reported in Table S2. Citations for compositional equivalence for stacked trait

351

products are provided in Table S3.

352 353

References

354

1.

Callaway, E., Domestication: The birth of rice. Nature 2014, 514, S58-9.

355

2.

Sang, T.; Ge, S., Understanding rice domestication and implications for cultivar improvement.

356

Current opinion in plant biology 2013, 16, 139-46.

357

3.

358

MacIntosh, S.; Pohl, M.; Rickard, C.; Tagliani, L.; Weber, N., Plants with genetically modified events

359

combined by conventional breeding: An assessment of the need for additional regulatory data. Food

360

Chem. Toxicol. 2011, 49, 1-7.

361

4.

362

Editor's choice: Evaluating the potential for adverse interactions within genetically engineered breeding

363

stacks. Plant Physiology 2013, 161, 1587-1594.

364

5.

365

Commission, Joint FAO/WHO Food Standards Programme, Food and Agriculture Organization of the

366

United Nations: Rome, Italy, 2009; Vol. Second Edition.

367

6.

368

petitions/petitions/petition-status. 2017.

369

7.

370

organism (GMO), rDNA or transgenic] crop cultivars. Plant biotechnology journal 2008, 6, 2-12.

Pilacinski, W.; Crawford, A.; Downey, R.; Harvey, B.; Huber, S.; Hunst, P.; Lahman, L. K.;

Steiner, H.-Y.; Halpin, C.; Jez, J. M.; Kough, J.; Parrott, W.; Underhill, L.; Weber, N.; Hannah, L. C.,

Codex Alimentarius, Foods derived from modern biotechnology. In Codex Alimentarius

USDA,

https://www.aphis.usda.gov/aphis/ourfocus/biotechnology/permits-notifications-

McHughen, A.; Smyth, S., US regulatory system for genetically modified [genetically modified

ACS Paragon Plus Environment

Page 18 of 33

Page 19 of 33

Journal of Agricultural and Food Chemistry

371

8.

Joseph, M.; Gopalakrishnan, S.; Sharma, R. K.; Singh, V. P.; Singh, A. K.; Singh, N. K.; Mohapatra,

372

T., Combining bacterial blight resistance and Basmati quality characteristics by phenotypic and

373

molecular marker-assisted selection in rice. Mol Breeding 2004, 13, 377-387.

374

9.

375

Sparks, O.; Urquhart, W.; Ward, J. M.; Vicini, J. L., Bringing New Plant Varieties to Market: Plant Breeding

376

and Selection Practices Advance Beneficial Characteristics while Minimizing Unintended Changes. Crop

377

Science 2017, 57, 2906-2921.

378

10.

Biotradestatus, Biotradestatus.com. 2017.

379

11.

Drury, S. M.; Reynolds, T. L.; Ridley, W. P.; Bogdanova, N.; Riordan, S.; Nemeth, M. A.; Sorbet, R.;

380

Trujillo, W. A.; Breeze, M. L., Composition of Forage and Grain from Second-Generation Insect-Protected

381

Corn MON 89034 Is Equivalent to That of Conventional Corn (Zea mays L.). Journal of Agricultural and

382

Food Chemistry 2008, 56, 4623-4630.

383

12.

384

Zhu, E.; Ridley, W. P., Compositions of Seed, Forage, and Processed Fractions from Insect-Protected

385

Soybean MON 87701 Are Equivalent to Those of Conventional Soybean. Journal of Agricultural and Food

386

Chemistry 2009, 57, 11360-11369.

387

13.

388

Dharmasri, C.; Golbach, J.; Guo, R.; Maxwell, C.; Privalle, L.; Rogers, H.; Liu, K.; Shan, G. M.; Yarnall, M.;

389

Thiede, D.; Gillikin, N., Validation of a Method for Quantitation of Soybean Lectin in Commercial

390

Varieties. J Am Oil Chem Soc 2015, 92, 1085-1092.

391

14.

392

Development, O. f. E. C.-o. a., Ed. Paris, France, 1993.

393

15.

394

pp 22984-23005.

Glenn, K. C.; Alsop, B.; Bell, E.; Goley, M.; Jenkinson, J.; Liu, B.; Martin, C.; Parrott, W.; Souder, C.;

Berman, K. H.; Harrigan, G. G.; Riordan, S. G.; Nemeth, M. A.; Hanson, C.; Smith, M.; Sorbet, R.;

Breeze, M. L.; Leyva-Guerrero, E.; Yeaman, G. R.; Dudin, Y.; Akel, R.; Brune, P.; Claussen, F.;

OECD, Safety evaluation of foods derived by modern biotechnology: Concepts and principles. In

U.S. FDA, Statement of policy: Foods derived from new plant varieties. Federal Register 57 1992,

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

395

16.

Cong, B.; Maxwell, C.; Luck, S.; Vespestad, D.; Richard, K.; Mickelson, J.; Zhong, C., Genotypic and

396

Environmental Impact on Natural Variation of Nutrient Composition in 50 Non Genetically Modified

397

Commercial Maize Hybrids in North America. J Agric Food Chem 2015, 63, 5321-34.

398

17.

399

Glenn, K. C., Natural variation in crop composition and the impact of transgenesis. Nature Biotechnology

400

2010, 28, 402-404.

401

18.

402

Szuma, K.; Sabbatini, J.; Srinivasan, J. R.; Tilton, G. B.; Venkatesh, T. V., Report: Release of the

403

International Life Sciences Institute Crop Composition Database Version 5. Journal of Food Composition

404

and Analysis 2016, 51, 106-111.

405

19.

406

herbicide-tolerant, increased oleic acid genetically modified soybean MON 87705 for food and feed uses,

407

import and processing under Regulation (EC) No 1829/2003 from Monsanto. EFSA Journal 2012, 10.

408

20.

409

stacked genetically modified events: To assess or not to assess? Trends in Biotechnology 2014, 32, 70-73.

410

21.

411

max L.) MON 87708 and MON 87708 x MON 89788 Are Compositionally Equivalent to Conventional

412

Soybean. J Agric Food Chem 2017, 65, 8037-8045.

413

22.

414

Belgium, 2013.

415

23.

416

genome plasticity and its relevance to food and feed safety of genetically engineered breeding stacks.

417

Plant Physiology 2012, 160, 1842-1853.

Harrigan, G. G.; Lundry, D.; Drury, S.; Berman, K.; Riordan, S. G.; Nemeth, M. A.; Ridley, W. P.;

Sult, T.; Barthet, V. J.; Bennett, L.; Edwards, A.; Fast, B.; Gillikin, N.; Launis, K.; New, S.; Rogers-

EFSA, Scientific opinon on application (EFSA-GMO-NL-2010-78) for the placing on the market of

Kok, E. J.; Pedersen, J.; Onori, R.; Sowa, S.; Schauzu, M.; De Schrijver, A.; Teeri, T. H., Plants with

Taylor, M.; Bickel, A.; Mannion, R.; Bell, E.; Harrigan, G. G., Dicamba-Tolerant Soybeans (Glycine

EC, Commission Implementing Regulation (EU) No 503/2013. In Commission, E., Ed. Brussels,

Weber, N.; Halpin, C.; Hannah, L. C.; Jez, J. M.; Kough, J.; Parrott, W., Editor's choice: Crop

ACS Paragon Plus Environment

Page 20 of 33

Page 21 of 33

Journal of Agricultural and Food Chemistry

418

24.

Food Safety Commission of Japan, Soybean lines generated through cross-breeeding of MON

419

87705, MON 87708, and MON 89788: Summary. Food Safety 2016, 4, 169-172.

420

25.

421

of risk assessment strategies for food and feed uses of stacked GM events. Plant biotechnology journal

422

2016, 14, 1899-913.

423

26.

424

Comparison of the forage and grain composition from insect-protected and glyphosate-tolerant MON

425

88017 corn to conventional corn (Zea mays L.). Journal of Agricultural and Food Chemistry 2007, 55,

426

4034-4042.

427

27.

428

Grain and Forage from MON 87427, an Inducible Male Sterile and Tissue Selective Glyphosate-Tolerant

429

Maize Product for Hybrid Seed Production. Journal of Agricultural and Food Chemistry 2014, 62, 1964-

430

1973.

431

28.

432

Schmidt, J.; Anderson, J. A.; Weber, N. N.; Herman, R. A.; Evans, S. L., Transgenic maize event TC1507:

433

Global status of food, feed, and environmental safety. GM Crops & Food 2015, 6, 80-102.

434

29.

435

assessment of event DAS-59122-7 maize using substantial equivalence. Regulatory Toxicology and

436

Pharmacology 2007, 47, 37-47.

437

30.

438

L.; Sorbet, R., Composition of grain, forage, and processed fractions from second-generation glyphosate-

439

tolerant soybean, MON 89788, is equivalent to that of conventional soybean (Glycine max L.). Journal of

440

Agricultural and Food Chemistry 2008, 56, 4611-4622.

Kramer, C.; Brune, P.; McDonald, J.; Nesbitt, M.; Sauve, A.; Storck-Weyhermueller, S., Evolution

McCann, M. C.; Trujillo, W. A.; Riordan, S. G.; Sorbet, R.; Bogdanova, N. N.; Sidhu, R. S.,

Venkatesh, T. V.; Breeze, M. L.; Liu, K.; Harrigan, G. G.; Culler, A. H., Compositional Analysis of

Baktavachalam, G. B.; Delaney, B.; Fisher, T. L.; Ladics, G. S.; Layton, R. J.; Locke, M. E. H.;

Herman, R. A.; Storer, N. P.; Phillips, A. M.; Prochaska, L. M.; Windels, P., Compositional

Lundry, D. R.; Ridley, W. P.; Meyer, J. J.; Riordan, S. G.; Nemeth, M. A.; Trujillo, W. A.; Breeze, M.

441

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

442

ACS Paragon Plus Environment

Page 22 of 33

Page 23 of 33

Journal of Agricultural and Food Chemistry

443 444

Figure Captions

445

Figure 1. Protein levels in maize and soybean grain.

446

The range of total protein is shown, with protein expressed as percent dry weight. For each

447

pair, the dark grey bar represents the range of observed protein values for the indicated GE

448

substance, and the pale grey bar represents the range of observed protein values for a related

449

conventional variety (“control”) that was grown concurrently. The medium grey bar at the far

450

right of each panel represents the range of protein values reported for the respective crop in

451

the ILSI Crop Composition Database (ILSI CCBD).

452

A. Protein levels in maize grain. Stack 1 is MON 87427 x MON 89034 x MON 88017, Stack 2 is

453

MON 89034 × TC1507 × MON 88017 × DAS-59122-7, and Stack 3 is MON 87427 x MON 89034 ×

454

TC1507 × MON 88017 × DAS-59122-7.

455

B. Protein levels in harvested soybean seed. Stack 1 is MON 87705 x MON 89788, and Stack 2

456

is MON 87705 x MON 87708 x MON 89788.

457

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 24 of 33

Table 1. Key traits of interest for the single trait products combined through conventional breeding in the assessed stacked trait products Citationsa

Crop

Product

Key Trait(s) of interest

Maize (Zea mays)

MON 89034

Protection against target aboveDrury et al, 2008(11) ground pests, through expression of Cry1A.105 and Cry2Ab2

MON 88017

Protection against target below ground pests, through expression of Cry3Bb1; tolerance to glyphosate herbicide through expression of CP4 EPSPS Tissue-selective tolerance to glyphosate herbicide (through expression of CP4 EPSPS), to facilitate production of viable hybrid maize seed Protection against target aboveground pests through expression of Cry1F

MON 87427

TC1507

DAS-59122-7

McCann et al., 2007(26)

Venkatesh et al, 2014(27); additional data provided in this publication

Baktavachalam 2015(28)

et

Protection against target below- Herman et al, 2007(29) ground pests, through expression of Cry34Ab1 and Cry 35Ab1); tolerance to glufosinate herbicide through expression of PAT Soybean MON 87705 Nutritionally-enhanced fatty acid This publication (Glycine profile, with increased level of max) oleic acid and decreased levels of palmitic, stearic, and linoleic acids MON 89788 Tolerance to glyphosate Lundry et al, 2008 (30) herbicide through expression of CP4 EPSPS MON 87708 Tolerance to dicamba herbicide Taylor et al, 2017(21) through expression of DMO a Reporting of compositional data for single trait product, where available

ACS Paragon Plus Environment

al.,

Page 25 of 33

Journal of Agricultural and Food Chemistry

Table 2. Compositional assessment of selected maize single trait and stacked trait products.

CONTROL

MON 87427 X MON 89034 × TC1507 × MON 88017 × DAS59122-7

9.69 0.42 11.10 8.52

c

9.13 0.41 10.35 6.77

3.69 0.13 3.98 3.47

4.16 0.085 4.49 3.88

4.13 0.084 4.29 4.00

1.62 0.036 1.82 1.42

1.56 0.038 1.67 1.48

1.47 0.052 1.66 1.25

c

84.96 0.42 86.22 83.58

84.70 0.56 85.62 83.63

84.51 0.57 85.76 82.96

84.68 0.42 86.16 83.43

9.12 0.060 9.34 8.91

11.08 0.26 11.69 10.65

10.54 0.26 11.08 10.15

11.05 0.12 11.39 10.52

CONTROL

MON 89034 × TC1507 × MON 88017 × DAS59122-7

MON 87427

CONTROL

MON a 88017

CONTROL

MON a 89034

CONTROL

MON 87427 X MON 89034 X MON 88017

10.05 0.63 11.35 8.46

10.26 0.63 11.92 8.62

12.51 0.35 13.00 11.63

12.28 0.35 13.82 11.22

10.43 0.42 11.98 8.54

10.36 0.42 11.52 9.22

10.03 0.63 11.08 8.85

10.26 0.63 11.92 8.62

3.50 0.13 3.83 3.13

3.69 0.13 3.98 3.47

3.64 0.13 3.96 3.44

3.79 0.13 4.36 3.53

3.32 0.069 3.89 3.05

3.29 0.069 3.75 3.05

3.67 0.13 3.93 3.19

1.58 0.036 1.81 1.43

1.56 0.038 1.67 1.48

1.54 0.077 1.68 1.31

1.59 0.077 1.97 1.23

1.41 0.036 1.56 1.25

1.39 0.036 1.51 1.28

84.88 0.56 86.33 83.60

84.51 0.57 85.76 82.96

82.32 0.40 83.39 81.61

82.33 0.40 83.62 80.67

84.85 0.42 86.52 83.29

10.54 0.26 11.08 10.15

10.24 0.43 10.52 10.07

11.27 0.43 14.57 10.14

9.19 0.060 9.46 8.98

CONTROL

ILSI b CCDB

10.06 0.20 11.27 8.78

9.21 0.20 10.51 7.44

17.26 5.72

3.74 0.089 4.37 3.19

c

3.33 0.089 3.78 2.74

7.83 1.36

1.34 0.051 1.55 1.06

1.34 0.040 1.81 1.02

1.33 0.040 1.86 0.96

6.28 0.62

85.39 0.41 87.85 84.08

84.86 0.23 86.58 83.95

c

86.13 0.23 88.12 84.93

89.7 77.4

10.63 0.12 11.28 10.40

11.05 0.11 11.69 10.40

c

11.67 0.11 13.26 10.87

26.55 6.81

Protein (% dw) MEAN S.E. MAX MIN Fat (% dw) MEAN S.E. MAX MIN Ash (% dw) MEAN S.E. MAX MIN Carbs (% dw) MEAN S.E. MAX MIN Palmitic Acid (% Total FA) MEAN S.E. MAX MIN

c

c

10.91 0.26 11.52 10.44

c

ACS Paragon Plus Environment

c

c

Journal of Agricultural and Food Chemistry

Page 26 of 33

Table 2, cont.

Stearic Acid (% Total FA) MEAN S.E. MAX MIN Oleic Acid (% Total FA) MEAN S.E. MAX MIN Linoleic Acid (% Total FA) MEAN S.E. MAX MIN Linolenic Acid (% Total FA) MEAN S.E. MAX MIN

1.82 0.021 1.87 1.76

2.01 0.091 2.19 1.83

1.90 0.091 2.07 1.77

2.10 0.080 2.40 1.90

2.01 0.079 2.19 1.81

2.13 0.049 2.59 1.85

22.87 0.23 23.51 21.43

24.96 0.34 25.75 23.38

24.84 0.34 26.66 23.62

23.55 0.92 25.41 21.94

23.52 0.92 25.71 21.74

32.20 0.78 34.02 30.43

32.24 0.78 33.66 30.74

62.85 0.39 63.72 61.86

61.52 0.39 63.18 59.10

61.82 0.40 63.61 60.85

62.07 0.40 63.41 60.51

61.33 1.28 63.20 58.62

62.06 1.28 64.09 59.18

52.81 0.75 54.37 51.10

1.21 0.062 1.26 1.15

1.32 0.062 1.77 1.19

1.19 0.027 1.23 1.12

1.22 0.027 1.43 1.15

1.23 0.014 1.28 1.20

c

1.20 0.014 1.22 1.18

1.01 0.016 1.04 0.98

CONTROL

MON a 89034

1.90 0.091 2.07 1.77

2.01 0.073 2.19 1.80

2.07 0.073 2.23 1.76

23.52 0.92 25.71 21.74

22.74 0.23 23.53 22.20

60.84 1.28 62.70 57.61

62.06 1.28 64.09 59.18

1.20 0.014 1.26 1.13

1.20 0.014 1.22 1.18

c

c

24.28 0.92 26.62 22.84

c

CONTROL

1.89 0.021 2.03 1.79

MON a 88017

1.97 0.091 2.17 1.81

CONTROL

CONTROL

MON 87427 X MON 89034 X MON 88017

CONTROL

MON 87427

MON 89034 × TC1507 × MON 88017 × DAS59122-7

MON 87427 X MON 89034 × TC1507 × MON 88017 × DAS59122-7

c

c

c

c

ACS Paragon Plus Environment

CONTROL

ILSI b CCDB

2.00 0.049 2.40 1.76

3.83 1.02

23.02 0.32 25.05 19.86

22.50 0.32 24.01 20.22

42.81 16.38

53.29 0.75 54.98 51.95

61.65 0.26 64.12 59.86

61.69 0.26 63.59 60.58

67.68 34.27

1.01 0.015 1.10 0.92

1.21 0.024 1.40 1.10

c

1.25 0.024 1.53 1.15

2.33 0.55

c

c

Page 27 of 33

Journal of Agricultural and Food Chemistry

Table 2, cont.

CONTROL

CONTROL

MON a 88017

CONTROL

MON a 89034

CONTROL

MON 87427 X MON 89034 X MON 88017

0.96 0.031 1.04 0.87

1.02 0.031 1.12 0.94

0.95 0.043 1.05 0.83

0.89 0.043 1.03 0.72

0.75 0.050 0.87 0.53

0.73 0.050 0.88 0.56

1.03 0.031 1.07 0.93

1.02 0.031 1.12 0.94

1.00 0.055 1.08 0.89

0.92 0.054 1.10 0.71

0.94 0.020 1.10 0.76

0.14 0.028 0.21 0.098

0.15 0.029 0.21 0.11

0.17 0.013 0.20 0.14

0.17 0.013 0.23 0.14

-

-

0.15 0.028 0.21 0.093

0.15 0.029 0.21 0.11

0.086 0.019 0.14 0.028

0.10 0.019 0.13 0.028

0.26 0.0096 0.33 0.17

MON 87427

Phytic Acid (% dw) MEAN S.E. MAX MIN Raffinose (% dw) MEAN S.E. MAX MIN

CONTROL

MON 89034 × TC1507 × MON 88017 × DAS59122-7

MON 87427 X MON 89034 × TC1507 × MON 88017 × DAS59122-7

c

a

c

c

CONTROL

ILSI b CCDB

0.90 0.020 1.01 0.66

1.94 0.11

0.24 0.0096 0.28 0.19

0.47 0.02

Composition data shown have been previously reported (MON 88017(26); MON 89034(11)); they are included here for comparison purposes. ILSI Crop Composition Database, Version 6.0; accessed 8/3/17 (www.crop.composition.com) c indicates statistical significance at p