Published 2020-11-12

This post is also available in Swedish

Gene scissors: benefits to environment and humankind obstructed by legislation

Since this year’s Nobel Prize in Chemistry was announced, ‘gene scissors’ have received a great deal of attention. In Mistra Biotech, researchers have used the method to develop potato varieties that have smaller chemical and energy needs, while simultaneously having more resistance to blight and optimised starch quality. But for these varieties to reach the market, and to promote more sustainable agriculture, EU legislation needs to be clarified.

Not far from Alnarp in Skåne, a potato variety that is resistant to late blight is being grown on a trial basis. Potatoes are one of the most disease-prone crops and, in particular, late blight is the biggest threat. Controlling it accounts for a quarter of the use of fungicides in Swedish farming. The potatoes now being grown in field trials have been developed in the Mistra Biotech research programme using the CRISPR-Cas9 method, popularly known as ‘gene scissors’. The agricultural industry is part-funding the field trials.

Unlike conventional genetic modification (GM), where genes are moved between organisms and new gene combinations thus created, gene scissors are used mainly to modify the crop’s own genes. Erik Andreasson, Professor of Plant Protection and Head of the Resistance Biology Unit at the Swedish University of Agricultural Sciences (SLU), explains.

King Edward, the most common potato variety in Sweden, is the one used in the work, according to Erik Andreasson, Professor of Plant Protection and Head of the Resistance Biology Unit at SLU.

‘This means you can make more specific modifications, with more expected results, than in traditional processing. With the gene scissors, we cut the genes that make the potatoes vulnerable to late blight, while retaining all other agronomic properties, such as the potato’s size, taste and cooking time. The reasons we chose to start the experiments with potatoes are that it’s a crop that’s heavily sprayed and relatively easy to modify. The mutations we create with the gene scissors might just as well occur spontaneously in nature.’

The latter is also a reason why many think that the method should not fall under GM legislation. According to a number of SLU researchers, this legislation is now obstructing the enormous progress in plant breeding that gene scissors can bring, by posing a risk of society — the environment, climate and people — missing out on great potential benefits. In many countries outside the EU, genetically modified crops are grown without any special GM regulation, and these may be come to be imported.

However, although the legal landscape is currently unclear, there is great interest from the farming industry. Right now, Andreasson’s research group is studying gene combinations, testing various types of ‘cut’ and seeking to understand unknown genes.

‘The field studies are intended to provide answers as to how far gene scissors can affect various genes and whether there may be any side effects when we cut out gene functions. But we’re also studying integrated cultivation methods and low-risk preparations of various types. It looks promising, but we’re not there yet. What’s exciting is that we now have completely new genes that should be viable in more crops than potatoes.’

Subject to GM legislation

Potatoes have been at the centre of another project using CRISPR-Cas9 technology. Jointly with the Swedish Starch Producers’ Association, researchers have developed a potato that produces only one of the two types of starch in potatoes: amylopectin, which provides a starch quality that has a long shelf life in industrial and food products. Today, to achieve storage stability, the starch undergoes chemical modification, which requires large quantities of chemicals and energy.

Mariette Andersson, Associate Professor at SLU. Photo: Viktor Wrange

‘With the new potato, the use of chemicals can be reduced by five to six thousand tonnes a year, in Sweden alone. And you should keep in mind that Sweden accounts for only a small fraction of the chemically modified starch on the market. So it can contribute to huge differences globally,’ says Mariette Andersson, Associate Professor at SLU.

In Mistra Biotech, another potato has been developed too; this ‘amylose potato’ has a low glycaemic index and healthy, disease-resistant starch.

‘For potatoes, we’ve seen that it’s a good method with favourable results. But CRISPR serves as a tool not only for crop improvement, but also for basic research,’ Andersson says.

The developed potato lines are managed in line with GM legislation but, according to Andersson, the farm sector is investing heavily in further development and trial cultivation near Kristianstad. The sector hopes to be able to put the potato on the market within a year or so — that is, if the legislation is amended or clarified.

Field trials with amylose potatoes. Photo: Mariette Andersson

Variously interpreted EU decisions

Dennis Eriksson, another research scientist at the Department of Plant Breeding and a participant in Mistra Biotech, interprets EU legislation more positively than many others. He believes that the question of gene (or genome) editing, like CRISPR, has brought the issue of GM to the fore. There are two schools of opinion. One interprets the legislation as technology-based: regardless of the technology used and the end product, the latter is a GM product. Instead, Eriksson wants to interpret the legislation as meaning that the end product, the plant in these cases, is what determines whether it is classified as a GM product.

Dennis Eriksson, researcher at the Department of Plant Breeding, SLU. Photo: Mårten Svensson

‘We need to go back to what the legal text actually says, namely that GM means a genetic modification that can’t occur naturally. Gene editing that uses gene scissors, for instance, has results that could very well arise spontaneously in nature. So gene editing shouldn’t be subject to GM legislation.’

In 2018, the European Court of Justice issued an advisory ruling. But Eriksson believes this too is open to interpretation. The ruling states that new techniques for mutagenesis (a collective term for methods used to produce DNA mutations, ed.) result in products that are subject to regulation under GM legislation. Nevertheless, certain mutagenesis techniques used by plant breeders for many years — including the method used extensively since the mid-20th century to provoke the mutations randomly with radiation or chemicals — are already exempt from the legislation.

‘What hasn’t been clarified is whether what the Court terms “new mutagenesis techniques” amount to exactly the same thing as gene editing, in the legal sense. Researchers and lawyers sometimes speak different languages, figuratively speaking.’

Starch from an amylose potato. Photo: Mariette Andersson

A survey of novel genomic techniques is currently under way in the European Commission, and is due to be presented in April 2021. But the risk is that this, too, will be insufficiently specific and lead neither to changes in the law nor to new techniques being exempted from the GM definition, according to Eriksson.

As for the field trials near Alnarp, the cultivation is subject to GM legislation at present, but in Sweden the licensing process for experimental growing is streamlined and no fencing is required around the plots, Andreasson says. And despite obstacles in the current legislation, he emphasises that this is a wonderfully exciting area of ​​research. Gene scissors are an excellent tool in more basic research on how genes function.

‘Then, of course, we want the products to be used. As a scientist, I see it as my task to demonstrate the positive environmental effects and the fact that it solves the problems of antibiotic resistance and plant protection products without adverse effects. Field trials of resistance make the work more visual and are a good arena for communication.’