Publication cannot fulfil promise of identifying genome-edited plants

In their article of 7 September 2020, Chhalliyil and colleagues [1] present a method in the journal Foods that is supposed to allow the identification of genome-edited crops. The authors conclude that with the help of this procedure, plants produced with modern genome editing methods can now be detected in food, feed and seeds in accordance with the legal requirements applicable in Europe. A detection method is required for the approval of a genetically modified plant in Europe.

The company Cibus US LLC markets herbicide-tolerant canola lines, which differ from each other by specific point mutations, reflected in tolerances to different herbicides. The point mutations are described in detail by the company in its patents and applications, together with the respective underlying breeding methods. In some of the lines, the point mutations arose from the genome editing method oligonucleotide-directed mutagenesis (ODM), in others from spontaneous mutations (somaclonal variations). The Canadian authorities have made all information on Cibus canola public, as has the company itself.

The authors developed tests based on quantitative polymerase chain reaction (qPCR) that can specifically and reproducibly detect the respective point mutation of a given canola line. The detection of (a priori known) point mutations by PCR described here is a method that has been routinely used for many years in science, breeding practice and in the laboratories of the competent GMO monitoring authorities and is not a scientific novelty. However, the detection of a point mutation does not allow any conclusion to be drawn as to how it arose. This is also emphasised in the reports on this publication by the authorities in the EU and Germany. The state of the art in science and technology is not changed in any way by this publication.

This is also made clear by the fact that the authors wrongly assumed that they had detected a mutation caused by ODM in one of the canola lines investigated. However, the examined line carries a spontaneous mutation. This clearly shows that while it is possible to detect a mutation, it is not possible to draw conclusions about the underlying origin of this mutation (its identifiability).

The publication by Chhalliyil et al. does not add any new knowledge to the current state of science and technology. Rather, it proves that it is not possible to distinguish genome-edited plants from plants with spontaneously occurring mutations. Without prior knowledge of the production process, no statement can therefore be made as to whether or not the plant is a GMO within the meaning of the ECJ ruling.

[1] Chhalliyil et al., 2020. A real-time quantitative PCR method specific for detection and quantification of the first commercialized genome-edited plant. Foods, 9, 1245.

published: 18. September 2020