Gene editing in plant breeding – a precision tool for better potatoes

– CRISPR is a powerful tool in plant breeding because it allows  introducing very precise changes to a plant’s DNA, says Matías González, postdoctoral researcher at the Department of Plant Breeding.

In every plant cell there is DNA that determines the plant’s characteristics. When the enzyme Cas9 is combined with a guide-RNA that directs it to the correct location, Cas9 acts like molecular scissors that cut the DNA with high precision. When the cell subsequently repairs the cut, a modification may arise.

Because the process is preceded by careful mapping of the plant’s genome, it is possible to make targeted changes to specific genes of interest.

The technique is particularly useful in crops such as potato, which have a complex genome with four copies of each chromosome, and are usually propagated through cloning rather than by seed. These characteristics make conventional breeding slow and challenging.

Small changes of great importance

Matías González completed his doctoral thesis at the University of Buenos Aires in Argentina on the use of CRISPR/Cas9 to improve traits in potato. He is now continuing his research at the Department of Plant Breeding at SLU, because of its recognised expertise in new genomic techniques.

– My research focuses on using new genomic techniques to better understand how potatoes produce starch, says Matías González. Starch is not only an important energy source in our diet, but also a significant renewable raw material for many different applications ranging from food production to paper and textiles.

Gene editing involves altering a plant’s genetic composition. A gene can be removed, switched off, or modified in a fine-tuned way. Such a change could often occur naturally, but gene editing allows the process to be achieved more quickly.

– With CRISPR, we can start from an established potato variety and introduce one or a few specific genetic changes to add new beneficial traits, such as improved starch quality or disease resistance, explains Matías González. This can be done without altering the rest of the plant’s genetic background.

Precision leads to safer outcomes

– In many cases, the edits made using CRISPR/Cas9 are fewer and more targeted than those introduced by other techniques, such as chemical or radiation-based mutagenesis, which have been used safely in agriculture for decades, says Matías González.

As with all technologies, however, safety depends on how it is used.

– From a technical perspective, CRISPR can be considered a safe tool because it is typically used to introduce small, precise changes in a plant’s DNA, resulting in modifications that could also arise in nature, he notes.

– It is therefore not the technique itself that should be assessed as safe or unsafe, but the final outcome. The edited plant must be evaluated to determine whether the result is as intended.

New regulations create opportunities

The preliminary European agreement on new genomic techniques (NGT) could create important opportunities for plant research and agriculture, as it entails regulatory relief compared with previous legislation on genetically modified crops. This could benefit the potato research group.

– Many of the plants produced in our research would fall within the NGT1 category, which includes plants with genetic changes that could also occur naturally or through conventional breeding.

This means that new varieties developed using gene-editing technology could be regulated in a similar way to traditionally bred varieties, although labelling would still be required for seed material. This, in turn, would make it easier to bring new plant varieties into use and make them available to farmers and consumers.

The final step in the legislative process is approval by the European Parliament, which is expected to take place in spring 2026.

Advances in more sophisticated applications of gene editing

Traditional CRISPR methods typically produce small changes in DNA, which is highly useful for studying gene function and developing new traits. However, some important traits require more precise or complex modifications, such as inserting or replacing larger DNA sequences at specific locations in the genome.

– Part of my research focuses on making these advanced edits more efficient in potato, says Matías González. We are making good progress and can now introduce targeted DNA insertions with promising efficiency. Importantly, we use DNA sequences that already exist within the potato gene pool, ensuring that no foreign DNA is present in the final edited plants.

Multiple techniques in the toolbox

– In our research group, we use a method in which individual potato cells from leaves are treated with CRISPR tools and then regenerated into full plants. This process leaves only the intended genetic change in the final plant, without introducing foreign DNA.

– This method allows us to develop and improve potato varieties faster and predictably. However, this does not mean that CRISPR will replace conventional breeding or other techniques. On the contrary, it is a complementary tool in the plant breeding toolbox that can be used in benefit of improved varieties.

How researchers improve potatoes using CRISPR/Cas9

Doctoral student Luboš Říha demonstrates how CRISPR/Cas9 is used to improve traits in potato.

Photo: Johanna Grundström/Matías González