Can Genome-Editing Help Tackle Climate Change?

Updated: May 31, 2019

by Timo Metz

The Matanuska banana plantation in Northern Mozambique has become undesirably famous. In the beginning of the 19th century, banana plants were hit by the so-called Panama disease, wiping out entire harvests. In the 1960s, a new variety of banana – the Cavendish – resistant against the Panama disease, arrived on the market and became the most common banana variety found today. However, roughly two decades ago, a new type of the Panama disease that also infects the Cavendish emerged in Asia and made its way to other continents. The Matanuska banana plantation was one of the first plantations in Africa to be hit. With around half a million people in Mozambique working in banana plantations, and bananas being an important source for labour and nutrition, there are deep fears surrounding the disease’s continental spread. Hope therefore lies in the creation of new resistant varieties. As bananas are infertile, causing each plant on a field to be genetically identical to each other, a resistant variety is unlikely to arise by chance. Thus, researchers are pinning their hopes on new, genetic, techniques to develop new crop varieties, with the most notable being ‘genome-editing’.

For thousands of years, people have relied on selective breeding to improve crop plants and reap the benefits of higher yield and stress tolerance. Modern crop plants are genetically distant from their wild ancestors. For example, the wild ancestor of modern corn, Teosinte, is significantly smaller and in many ways different than the crop grown today. In the last decade, improvements in genetic research have led to the discovery of so-called ‘genome-editing’ techniques that offer new possibilities for genetically altering and improving crop plants. This technique, not to be confused with classic genetic engineering, aims to intentionally introduce ‘breaks’ at selected parts of the DNA-strand. During the DNA’s natural repair, biological errors can result in genetic alteration which can lead to potentially beneficial traits. Such ‘breaks’ can occur in nature through, for instance exposure to high-energy radiation from sunlight, causing natural mutations. Genome-Editing techniques are thereby distinct from classic genetic engineering techniques, which typically aim to introduce the external DNA of other organisms to transplant whole genes, which are the genetic basis of beneficial traits.

Genome-editing presents major opportunities compared to conventional breeding. The success of conventional breeding relies heavily on the random genetic variation present in the gene pool of a species and the possibilities of crossing. Genetic variation arises from spontaneous mutation during evolution, or by forced and unspecific mutations with radiation and chemicals in recent breeding. For wheat, during one generation of propagation, 100 spots on the genome can be subject to mutation. However, as conventional breeding techniques are not targeted, modifying a single trait costs time and money agriculturalists can ill-afford. Crossing success can also be impaired as some desirable traits are hard to be isolated when transferred, which is why a combination of beneficial traits (e.g. higher-yield and a certain stress tolerance) is so hard to obtain by conventional means. Genome-editing in combination with modern genomics can help to identify genomic regions which are responsible for specific traits and help to modify them specifically for relatively low cost. It is thereby more precise and effective than conventional breeding while relying on similar biological background processes as conventional mutation.

While classic genetic engineering has much stigma attached to it, scientific and research bodies have high hopes for genome-editing to accelerate crop breeding. The technique can be used to create crops that are more stress tolerant, higher-yielding, or even resistant against certain diseases. For example, genome-editing was already used for developing a cultivar of wheat, which is resistant against powdery mildew. This is especially interesting, as wheat is hexaploid (has six chromosomes), making it especially difficult to obtain such specific traits through conventional breeding. Diseases are typically a major contributor to yield loss, with climate change being thought to further help diseases to spread. The usage of disease resistant varieties created with genome-editing could help towards creating a more resilient agriculture, using less CO2-intensive protection agents but at the same time stabilising yield in a changing climate.

The development of stress tolerant crops or crops that are more nutrient efficient or higher yielding could further help sustaining food security. Examples of stress tolerant crops created with genome-editing include drought tolerant wheat and corn, or salt tolerant rice. When plants use their land more efficiently, with higher yield, the need for land and fertilizer can be decreased. Using less land for farming leads to larger areas of land for conservation, which can also help protect biodiversity and ultimately decrease the impact of agriculture on the biosphere.

Genome editing should also be considered in relation to climate change. High food demand, especially in developing countries experiencing intense population growth, has culminated in increasing threats to food security significantly, worsened by climate change. In the past, increases in larger and more sustainable crop yields were accompanied by the use of CO2-intensive fertilizers and pesticides, and the excessive use of land. However, these unsustainable agricultural practices are playing a role in further fueling climate change. Fighting against and adapting to climate change demands the transition to less CO2-intensive agriculture and the necessity for crop varieties that are stress tolerant while still high-yielding. Newly developed crop varieties, most notably through genome-editing, could help in achieving those transitions.

Despite these seemingly universal benefits, genome-editing faces varied legal regimes worldwide. Many countries, notably the United States, follow a product-based regulation, meaning genome-edited crops are not administered under the same legal code as GM crops, providing the genome-edited crop is genetically identical to a crop created through conventional breeding. However, Europe follows a process-based regulation, leading to the European Court of Justice to recently classify genome-editing under the same law as classic genetic engineering. Just as with classic genetic engineering, the ‘precautionary principle’ takes priority here, in order to minimize risks when introducing new crop plants.

The EU’s decision originated from a case put forward by French NGOs. Most of them are not internationally known, but opposition to genome-editing is shared by many major environmental NGOs, including Greenpeace. The case was based on the fear that genome-editing posed similar risks and use cases to classic genetic engineering– which in the past have included the creation of herbicide resistant crop varieties by major seed companies, which would lead to increased use of herbicides (e.g. Monsanto’s Roundup Ready crop). The NGOs brought the claim to ensure that genome-editing was not totally deregulated. But even though genome-editing can be used to create herbicide-resistant crops, this argument makes an unfair victim of genome editing, since also conventional breeding can lead to the creation of herbicide-resistant crops. While the aims of a resilient agriculture are well-founded in these NGO’s, the claim put forward is dubious in its positive impact. Techniques which could solve problems associated with agriculture should be supported and be used for good, not blocked out of hand. Instead, the focus should be on more strongly regulating the usage of herbicides or herbicide-resistant crops, if that is where the problem lies.

Genome-editing being regulated in the same way as classic genetic engineering creates certain barriers to the sale of genome-edited crop. Studies and assessments, compulsory before permission is granted, can take years and are prohibitively expensive. Genome-editing therefore remains a technique predominantly used by major seed companies that can afford the long duration and high cost of patent application. As some of those companies also produce pesticides, it is likely that the created crop varieties will possess traits such as herbicide resistance, which make the purchase of herbicides necessary. Critics of the regulation further point out that conventional breeding techniques can include the use of chemicals or radiation in order to force mutations randomly to create new crop varieties by chance. For example, close to all durum used for pasta is created with this technique. Those techniques are considered less precise than genome-editing, yet are not subject to regulation.

A measured and sensible handling of the technology is needed to facilitate a safe, reliable, and publicly acceptable use of genome-editing. Public research for genome-editing in crop breeding should be promoted and funded to develop crop varieties with traits that are beneficial for combating climate change. Under current regulation, public research institutions are typically not able to obtain a patent for a particular crop based on genome-editing. This can be resolved by enabling governments to file a patent application for certain crop varieties, thus allowing these to be treated as open-source. Public research could also focus on actual necessities in crop design, independent of profit incentive. Seed varieties could then be used and bred by farmers in developing countries without the need to buy seeds from major companies, ensuring agricultural sovereignty is maintained. Research institutions could document the process of genome-editing and make sure that changes in DNA at the target sites are only those intended, minimising risk of unforeseen ecological consequences.

Looking past the sphere of scientific research, public concerns must be addressed. As it stands, the public still fears that genome-edited crops may not be safe. This makes it hard to find a market for genome-edited products. However, while safety is, of course, indispensable, it must be communicated that genome editing itself does not make a food unsafe. Education about the actual biological process of breeding techniques could help decouple genome-editing as a technique from images of megacorporations growing mutant seeds. The idea that genome editing can be used wisely to develop crop plants that possess desirable traits needs to be more widely disseminated.

Besides developing innovative crops, additional steps must be taken for a transition towards less CO2-intensive agriculture. Consumers could, for instance, shift their diets towards the consumption of more seasonal and regional food, and less meat. However, there is also a critical need for new and transformative ideas for addressing agriculture’s future challenges. Agriculture struggles with plant diseases and environmental stress, resulting in less yield or the CO2-intensive reliance on chemicals. With the help of genome-editing, agriculture can turn from the practice of chemistry to biology and address one of our biggest challenges for the future: feeding a world with a changing climate, while avoiding ecological damage.

Art by Jess Baker

Timo Metz holds a double Bachelor degree in Physics and Biology from Marburg University and currently starts his Master degree in Physics at Heidelberg University. His Bachelors thesis in Biology was in the field of Bioinformatics, creating an annotation of the Aethionema arabicumgenome. In Physics, he worked with the modelling of microplastic distributions in the environment. A member of the German green party, his topics of interest include ecology, climate change, environmental pollution, resilient agriculture and the transition of the energy system.

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