Gene-edited and other GM crops

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New review details failures of first-generation GM crops, points to unintended effects of new GM. Report by Claire Robinson

Will genetically modified gene-edited crops, foods and animals improve the sustainability of food and farming? A comprehensive new scientific review addresses this question by investigating the record of old-style transgenic GM crops and the potential and reality of newer gene-edited crops and animals. The review, by Dr Allison Wilson of the Bioscience Resource Project in the US, is titled, "Will gene-edited and other GM crops fail sustainable food systems?" and forms part of a forthcoming Elsevier book, Rethinking Food and Agriculture. It takes in GM golden rice, GM herbicide-tolerant (HT) crops, and GM Bt insecticidal crops, and looks at the unintended effects of both old-style GM crops and new gene-edited crops. It finds that "the widespread use of Bt and HT crops has led to the problematic development of pest resistance, superweeds, and secondary pests. In response to these problems, "farmers increased both insecticide and herbicide use. Some also increased tillage and other mechanical methods of weed control." The review notes that attempts to develop GM golden rice have been plagued with technical difficulties. These include unintended effects such as defective growth and performance and low levels of beta-carotene, the substance that is intended to be converted to vitamin A in the bodies of the malnourished people targeted for the rice. Other GM crops show a wide variety of unintended traits. Research on large populations of transformants – cells or organisms, such as plants, into which foreign DNA has been introduced – reveal frequent "defects in basic agronomic traits such as yield, height, stem, and leaf morphology" (structure). Contrary to claims by the GMO lobby that plants with unintended traits are screened out before they are brought to market, Dr Wilson points out that even commercialised GM crops contain many unintended traits, many of which have implications for sustainability. MON810 maize, for example, has numerous compositional differences compared with the non-GM parent crop, including increased lignin (which makes cell walls more rigid), the presence of an allergen, and increased moisture content. MON810 also has negative impacts on beneficial soil organisms. A table in the review (Table 13.1) lists examples of some of the many unintended traits that have been identified in commercial GM crops.

Will gene editing increase the precision and thus effectiveness of genetic engineering technologies? Dr Wilson writes that the evidence thus far shows that gene editing is "also prone" to introducing unintended effects. This is partly because virtually all gene editing protocols utilize standard GM techniques and also because "new evidence from both animals and plants indicates that gene editing itself can result in unintended mutations at or near the target site". Numerous studies cited in the review "support the conclusion that plant gene editing outcomes are imprecise and unpredictable, and that, depending on the combination of techniques used, gene editing can be highly mutagenic" (causing DNA damage). As with older-style GM, Dr Wilson notes, the number and type of unintended effects introduced using gene editing will depend in part on the new trait being introduced and in part on the unintended effects wrought on the genome by the techniques themselves. So contrary to the messaging of pro-GMO lobby groups and organisations, Dr Wilson says that there can be no shortcuts when it comes to regulating these techniques: "All benefits, hazards, and risks must therefore be assessed experimentally on a case-by-case basis for each independently derived nGM trait and crop... This should include whole genome sequencing comparisons with an isogenic line and -omic [molecular profiling] analyses." Dr Wilson concludes, "While in theory it might someday be possible to create a GM crop that meets the broad requirements of sustainable agriculture, in practice this seems highly unlikely to ever happen."

The findings of the new review are timely for the European Union. The European Commission's Farm to Fork Strategy of May 2020 plans to improve the sustainability of the food and agriculture chain – and the Commission thinks new GM techniques such as gene editing might play a part. By 2030 Farm to Fork plans to reduce the use of fertilisers by at least 20% and chemical pesticides by 50% and turn 25% of agricultural land over to organic farming. But the Farm to Fork report also contains a highly contentious statement that the Commission is "carrying out a study which will look at the potential of new genomic techniques to improve sustainability along the food supply chain". The Commission says, "new innovative techniques, including biotechnology and the development of bio-based products, may play a role in increasing sustainability, provided they are safe for consumers and the environment while bringing benefits for society as a whole". According to the Commission, new GM techniques can "accelerate the process of reducing dependency on pesticides". EU agriculture ministers gave their stamp of approval to Farm to Fork and were quick to seize the opportunity to push new GM, telling the media that the EU should make use of "new innovative" breeding techniques, including gene editing, to boost sustainability of food production. Both the agriculture ministers and the Commission need to carefully examine the findings of Dr Wilson's review, which offers crucial information for policymakers considering how to regulate new GM techniques. And the Commission must address all the points made in the review in its study on new GM and sustainability.