New breeding plant technologies - A regulatory conundrum

29 April 2017 - By: Cornelia Eisenach

New breeding plant technologies - A regulatory conundrum

GMO meal
The worlds first CRISPR lunch (probably). Photo: Stefan Jansson


By Cornelia Eisenach, University of Zürich

In a post-truth era, how do we communicate controversial science? The Science with Impact event at the SEB Annual Meeting 2017 in Gothenburg will address this question, and discuss the good, the bad and the ugly of past approaches.

Arguably, one of the ugliest communicat ion wars was fought over genetically modified organisms (GMOs), especially food crops. While some might still lick their wounds, the next generation of crops, bred through New Plant Breeding Technologies such as the Crispr/ Cas9 system, are already on our door step. But can these new crops be classified as GMOs? How they should be regulated is currently being discussed across the globe.

GMO or not GMO, that is the question

CRISPR/Cas9 is the new revolution in genetic engineering and many scientists are using it in their day-to-day research. CRISPR stands for clustered regularly interspaced short palindromic repeats, and Cas9 is a CRISPRassociated nuclease. The system is often described as molecular scissors. It can be used to precisely target a certain position in a genome where it cuts the DNA and during subsequent repair, base pairs can be deleted, modified or inserted (see Graphic I). While a moratorium has been advocated for its use on the human germ line1, it is being applied to modify plants and fungi used in food. Only last year, a white button mushroom engineered with CRISPR/Cas9 to reduce browning was approved by the US Department of Agriculture (USDA) for commercial use and without it being subject to regulation2

Graphic 1
GRAPHIC I. CRISPR/Cas9: how it works. CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats, and Cas for CRISPR associated. The Cas9 nuclease is guided to a specific target sequence in a genome by the guide RNA. It induces a DNA double-strand break for which it requires a short, conserved sequence called the protospacer-associated motif (PAM). The cut DNA is repaired by the cell’s repair system through non-homologous end joining. In this process, mutations can arise that disrupt gene function. If the introduction of a new DNA sequence is required, a donor-DNA is required for homology-directed repair. Image: Cornelia Eisenach and DataBase Center for Life Science (DBCLS), licensed under Creative Commons license.


 
With the CRISPR/Cas9 system, a crop genome can be modified to breed beneficial traits. It can be used to introduce foreign DNA, rendering the resultant crop a GMO. If it is used to induce point-mutations, the resultant crop cannot be distinguished from a conventional breed, because the CRISPR/ Cas9 system is removed from the crop after it has done its job. The mutation could have arisen spontaneously, or by other means of conventional breeding such as treatment with chemicals or radiation (see Graphic II). This is why scientists from China, USA and Germany have called to exempt so-called gene-edited crops from regulations that currently apply to GMOs3. The researchers argue that there is no scientific reason to distinguish between two mutated plants based on how the mutations were induced, i.e. either via conventional breeding or via gene-editing. Furthermore, using CRISPR/Cas9 to induce a mutation would lead to fewer unwanted effects in the genome than mutagenesis by chemicals or radiation.

 

Getting consensus

Regulatory authorities across the globe now need to decide on how to legislate gene-edited crops and, more generally, New Plant Breeding Technologies (NPBT, see explainer). And time is running out. Already in 2015, six EU member states judged that a herbicide-tolerant oilseed canola that had been modified using an older gene-editing technique was not to be classed as GMO under EU law. The German Federal Office of Consumer Protection and Food Safety allowed the US firm Cibus, which created the crop, to go ahead with field trials.

At the time the EU commission asked these countries to halt their approval and wait for their legal interpretation of EU law. Will it be interpreted to state that any organism that was created using genetic modification techniques is a GMO, i.e. a process-based interpretation, or does it also allow for a product-based interpretation, i.e. that any organism containing foreign DNA is a GMO? The European Commission already instated an expert group on NPBTs in 2007, and although the Commission’s interpretation was announced for the end of 2015, then postponed to spring 2016, an official document has yet to be released. Current events in France have pushed the ball even further afield: in October 2016, the French Government asked the European Court of Justice to rule whether NPBTs fall under EU law on GMOs and whether countries could ban these technologies4. A ruling, and therefore a judgement of the EU Commission, cannot be expected before 2018.

Making a meal of it

Someone who did not want to wait so long is Stefan Jansson. Professor at the University of Umeå in Sweden, he demonstrated how scientists can communicate the risks and benefits of New Plant Breeding Technologies. In the tradition of self-experimentation, he cooked and ate what was probably the world’s first CRISPR lunch using gene-edited kale. Jansson is one of the organisers of a session on ‘New breeding technologies in the plant sciences’ at the SEB meeting in Gothenburg 2017. “We succeeded in convincing a Swedish authority to state that, according to their interpretation, the plants could not be considered genetically modified in accordance to EU regulations as they do not contain any ‘foreign DNA’,” he writes in a blog documenting the experiment5. He grew the kale, which had been modified using the CRISPR/Cas9, in his own vegetable garden and when it came to harvest time, he invited the host of a Swedish radio station and cooked a CRISPR-kale pasta dish, the recipe of which can be found on his blog.

Exceptions to the rule

While in Europe the waiting game continues, the USA has recently taken a clearer stand. In January 2017, the USDA Animal and Plant Health Protection Service (Aphis) released documents which contain suggestions for new regulatory rules. Aphis advocates exempting crops produced by gene-editing from regulation but go even further: the authority also seems to want to exempt certain transgenic crops. Transgenic crops often contain sequences of plant pests such as the 35S promoter of the cauliflower mosaic virus or the left border sequence of Agrobacterium. But the authority states: “The experience has shown that the use of genetic material from plant pests has not resulted in the creation of plant pest risks in recipient organisms.” It did not refer to any systematic analysis of this experience, but the passage suggests that crops bred through Cisgenesis (see Graphic II) might no longer be regulated in the future. 

A ruling in the US is likely to impact on Europe, either politically or through import of potentially unclassified geneedited crops. Many organisations including those representing organic farmers are on the alert. Whether gene-editing results in changes that could be obtained through conventional breeding, or not, is not the crucial question. In the view of many organic farming organisations, manipulation of subcellular material is prohibited due to ethical considerations. So far, IFOAM, the European umbrella organisation of the organic movement, has called for NBPTs to be considered as GMOs, and its membership is expected to vote on the organic sector’s position in November 2017. So, are traditional fault lines of past communication wars set to open again? NBPTs could have benefits for organic farming: geneedited crops that do not contain foreign DNA could help to increase productivity without the use of herbicides and pesticides. It is up to scientists to communicate these benefits in engaging ways.

References:

1. http://www.nature.com/news/don-t-edit-the-humangerm-line-1.17111
2. http://www.nature.com/news/gene-edited-crisprmushroom-escapes-us-regulation-1.19754
3. http://www.nature.com/ng/journal/v48/n2/full/ng.3484.html
4. http://www.conseil-etat.fr/Actualites/Communiques/Organismes-obtenus-par mutagenese
5. https://www.blogg.umu.se/forskarbloggen/2016/09/future-garden-plants-are-here-a-diary-

 

 

 

 

GRAPHIC II. Comparison between conventional breeding technical, ‘classic’ GMOs and breeding through gene-editing such as by CRISPR/Cas9.

Image: Cornelia Eisenach, adapted from Marchman et al. (2015) Feasibility of new breeding techniques for organic farming. Trends in Plant Science 20: 426–434

 

 

Graphic 2
Category: Cross disciplinary
Share
Cornelia Eisenach- Author Profile

Cornelia Eisenach

Originally from Berlin, Cornelia completed her PhD research in Plant Cell and Molecular Biology at Glasgow University. Apart from researching plant ion channels she also helped to establish and contributed to the GIST, a Glasgow-based popular science magazine, worked at science outreach events with kids and gathered work experience at the BBC. Since 2013 she has been a post-doctoral research fellow at the University of Zürich, Switzerland, and works as a science writer for the SEB, the Neue Zürcher Zeitung and SciViews