SuppressEJ – Suppression of DNA end joining processes to promote precise and transgene-free genome editing in higher plants.

• Applicant: Dr. Tom Schreiber
• Subject Area: Plant Genetics and Genomics ; Plant Breeding and Plant Pathology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 569501188

Precise genome editing holds strong potential for plant breeding and basic research. Tools like CRISPR-Cas9 excel at gene knockouts but struggle with precise genome modifications via homologous recombination. This is because the resulting lesions are substrates for inaccurate end joining processes. Precise genome editing relies on homology-directed repair (HDR), which is underutilized due to the dominance of DNA end-joining (EJ) pathways, specifically classical (cNHEJ) and alternative (aNHEJ) mechanisms. These end joining mechanisms are also required for stable integration of Agrobacterium-delivered T-DNAs into plant genomes, the established method for plant genome editing which goes along with unwanted stable integration of foreign genetic material (transgenes). The goal of this proposal is to develop and apply efficient molecular suppressors of undesired plant EJ processes to increase the frequency of precise HDR-based genome editing events during plant transformation. Application of these suppressors is proposed to occur temporarily, simultaneously to DNA cleavage, avoiding pleiotropic effects on plant development. Efficient suppression of DNA EJ-mechanisms will reduce or even prevent unwanted stable integration of T-DNAs. The successful outcome of the project would strongly improve the efficiency of precise and transgene-free genome editing in higher plants, particularly relevant for plant species with significant economic or ecological implications. This technology may have a positive impact on public acceptance of genetically engineered plants.

• DFG Programme: Research Grants