Plants with stacked genetically modified events: to assess or not to assess?

Kok, E.J.; Pedersen, Jan W.; Onori, Roberta; Sowa, S.; Schauzu, M.; Schrijver, Adinda De; Teeri, Teemu H.

doi:10.1016/j.tibtech.2013.12.001

Cited by 38 publications

(26 citation statements)

References 8 publications

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“…Taken together, these data provide a strong rationale for revision of the current practices for food and feed safety assessments of stacked GM events through problem formulation focused on potential interactions resulting from the specific combination of GM events (Kok et al ., ; Steiner et al ., ; Weber et al ., ). Problem formulation approaches to risk assessment maximize the possibility of detecting effects that indicate potential risk (Raybould, ).…”

Section: Discussionmentioning

confidence: 99%

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Evolution of risk assessment strategies for food and feed uses of stacked GM events

Kramer

Brune

McDonald

et al. 2016

Plant Biotechnology Journal

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SummaryData requirements are not harmonized globally for the regulation of food and feed derived from stacked genetically modified (GM) events, produced by combining individual GM events through conventional breeding. The data required by some regulatory agencies have increased despite the absence of substantiated adverse effects to animals or humans from the consumption of GM crops. Data from studies conducted over a 15‐year period for several stacked GM event maize (Zea mays L.) products (Bt11 × GA21, Bt11 × MIR604, MIR604 × GA21, Bt11 × MIR604 × GA21, Bt11 × MIR162 × GA21 and Bt11 × MIR604 × MIR162 × GA21), together with their component single events, are presented. These data provide evidence that no substantial changes in composition, protein expression or insert stability have occurred after combining the single events through conventional breeding. An alternative food and feed risk assessment strategy for stacked GM events is suggested based on a problem formulation approach that utilizes (i) the outcome of the single event risk assessments, and (ii) the potential for interactions in the stack, based on an understanding of the mode of action of the transgenes and their products.

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Section: Discussionmentioning

confidence: 99%

“…More than 20 different GM crops with stacked events have been evaluated by EFSA and other regulatory agencies and in all cases EFSA concluded that there were no compositional, agronomic or phenotypic changes that would raise safety concerns (Kok et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Evolution of risk assessment strategies for food and feed uses of stacked GM events

Kramer

Brune

McDonald

et al. 2016

Plant Biotechnology Journal

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“…Overall, there is a few available data on transgene expression levels in both stacked and single transgene GM crops in the scientific literature. Although data on expression levels for stacked GM events are required for approval according to EU regulations (No 503/2013), these are rarely disclosed or they are considered insufficient [42, 96, 97]. Recent discussions about potential risks of stacked events, as well as the opinion of the European Food Safety Authority (EFSA) on those issues, have highlighted the lack of consensus with regard to whether such GMOs should be subject to specific assessments [98].…”

Section: Discussionmentioning

confidence: 99%

Levels of DNA methylation and transcript accumulation in leaves of transgenic maize varieties

et al. 2016

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BackgroundPrior to their release in the environment, transgenic crops are examined for their health and environmental safety. In addition, transgene expression needs to be consistent in order to express the introduced trait (e.g. insecticidal and/or herbicide tolerance). Moreover, data on expression levels for GM events are usually required for approval, but these are rarely disclosed or they are considered insufficient. On the other hand, biosafety regulators do not consider epigenetic regulation (e.g. DNA methylation, ncRNAs and histone modifications), which are broadly known to affect gene expression, within their risk assessment analyses. Here we report the results of a DNA methylation (bisulfite sequencing) and transgene transcript accumulation (RT-qPCR) analysis of four Bt-expressing single transgenic maize hybrids, under different genetic backgrounds, and a stacked transgenic hybrid expressing both insecticidal and herbicide tolerance traits.ResultsOur results showed differences in cytosine methylation levels in the FMV promoter and cry2Ab2 transgene of the four Bt-expressing hybrid varieties. The comparison between single and stacked hybrids under the same genetic background showed differences in the 35S promoter sequence. The results of transgene transcript accumulation levels showed differences in both cry1A.105 and cry2Ab2 transgenes among the four Bt-expressing hybrid varieties. The comparison between single and stacked hybrids showed difference for the cry2Ab2 transgene only.ConclusionsOverall, our results show differences in DNA methylation patterns in all varieties, as well as in transgene transcript accumulation levels. Although the detection of changes in DNA methylation and transgenic accumulation levels does not present a safety issue per se, it demonstrates the need for additional studies that focus on detecting possible safety implications of such changes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12302-016-0097-2) contains supplementary material, which is available to authorized users.

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“…In addition, a growing number of genes or regulatory elements have still been transferred into crop genomes to improve agronomic traits (Daniela et al, 2013). Once transgenic lines showing excellent agronomic performance are generated, the extensive testing and comprehensive analyses of these lines are necessary for biosafety assessment before being approved and entering into market (Codex Alimentarius Commission, 2003; European Food Safety Authority [EFSA], 2010; Kok et al, 2015). Among these, low copy number integration is the most favorable molecular profile for selecting the best events from putative lines (Kovalic et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Identification of Genomic Insertion and Flanking Sequence of G2-EPSPS and GAT Transgenes in Soybean Using Whole Genome Sequencing Method

Guo

Hong

et al. 2016

Front. Plant Sci.

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Molecular characterization of sequence flanking exogenous fragment insertion is essential for safety assessment and labeling of genetically modified organism (GMO). In this study, the T-DNA insertion sites and flanking sequences were identified in two newly developed transgenic glyphosate-tolerant soybeans GE-J16 and ZH10-6 based on whole genome sequencing (WGS) method. More than 22.4 Gb sequence data (∼21 × coverage) for each line was generated on Illumina HiSeq 2500 platform. The junction reads mapped to boundaries of T-DNA and flanking sequences in these two events were identified by comparing all sequencing reads with soybean reference genome and sequence of transgenic vector. The putative insertion loci and flanking sequences were further confirmed by PCR amplification, Sanger sequencing, and co-segregation analysis. All these analyses supported that exogenous T-DNA fragments were integrated in positions of Chr19: 50543767–50543792 and Chr17: 7980527–7980541 in these two transgenic lines. Identification of genomic insertion sites of G2-EPSPS and GAT transgenes will facilitate the utilization of their glyphosate-tolerant traits in soybean breeding program. These results also demonstrated that WGS was a cost-effective and rapid method for identifying sites of T-DNA insertions and flanking sequences in soybean.

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Plants with stacked genetically modified events: to assess or not to assess?

Cited by 38 publications

References 8 publications

Evolution of risk assessment strategies for food and feed uses of stacked GM events

Evolution of risk assessment strategies for food and feed uses of stacked GM events

Levels of DNA methylation and transcript accumulation in leaves of transgenic maize varieties

Identification of Genomic Insertion and Flanking Sequence of G2-EPSPS and GAT Transgenes in Soybean Using Whole Genome Sequencing Method

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