Implications of the EFSA Scientific Opinion on Site Directed Nucleases 1 and 2 for Risk Assessment of Genome-Edited Plants in the EU

Nils Rostoks

doi:10.3390/agronomy11030572

Abstract

Genome editing is a set of techniques for introducing targeted changes in genomes. It may be achieved by enzymes collectively called site-directed nucleases (SDN). Site-specificity of SDNs is provided either by the DNA binding domain of the protein molecule itself or by RNA molecule(s) that direct SDN to a specific site in the genome. In contrast to transgenesis resulting in the insertion of exogenous DNA, genome editing only affects specific endogenous sequences. Therefore, multiple jurisdictions around the world have exempted certain types of genome-edited organisms from national biosafety regulations completely, or on a case-by-case basis. In the EU, however, the ruling of the Court of Justice on the scope of mutagenesis exemption case C-528/16 indicated that the genome-edited organisms are subject to the GMO Directive, but the practical implications for stakeholders wishing to develop and authorize genome-edited products in the EU remain unclear. European Food Safety Authority in response to a request by European Commission has produced a scientific opinion on plants developed by SDN-1, SDN-2, and oligonucleotide-directed mutagenesis (ODM) genome editing techniques. In this review, I will (1) provide a conceptual background on GMO risk assessment in the EU; (2) will introduce the main conclusions of the EFSA opinion, and (3) will outline the potential impact on the risk assessment of genome-edited plants.

Highlights

Plant breeding harnesses existing genetic diversity and makes use of different tools to increase it
This case was considered by the European Food Safety Authority (EFSA) scientific opinion on molecular characterization (MC) and environmental risk assessment (ERA) of genetically modified plants (GMP), which concluded that the requirements of the European Union (EU) regulatory framework and existing EFSA guidelines are adequate for the risk assessment of SynBio products to be developed in the 10 years, specific requirements may not apply to all products [39]
The EFSA opinion concluded that the risk assessment methodology and the existing guidelines are sufficient, only partially applicable for risk assessment of genome-edited organisms

Summary

Introduction

Plant breeding harnesses existing genetic diversity and makes use of different tools to increase it. Editing of a genome can be done using different techniques, but they usually involve enzymes that can introduce double-stranded DNA breaks and are collectively called site-directed nucleases (SDN). Per request of the Council of the European Union (Council Decision (EU) 2019/1904), the EC is conducting an ongoing study involving input from the Member States and different stakeholders regarding the status of novel genomic techniques including genome editing. Within this framework, the European Commission (EC) mandated the European Food Safety Authority (EFSA) to issue a scientific opinion on the risk assessment of plants produced by the SDN-1, SDN-2, and oligonucleotide-directed mutagenesis (ODM) techniques. I will outline the main conclusions of the EFSA opinion and discuss the implications for risk assessment of genome-edited plant products in the EU

Context of Genome Editing within the Existing GMO Risk Assessment Framework

Targeted Mutations in Genomes

Off-Target Mutations in Genomes

Impact on the Risk Assessment of Genome-Edited Plants in the EU

Conclusions