What is the available evidence for the application of genome editing as a new tool for plant trait modification and the potential occurrence of associated off-target effects: a systematic map protocol

Abstract

Abstract Background Plant breeding is a developing process and breeding methods have continuously evolved over time. In recent years, genome editing techniques such as clustered regularly interspaced short palindromic repeats/CRISPR associated proteins (CRISPR/Cas), transcription activator-like effector nucleases (TALENs), zinc-finger nucleases (ZFN), meganucleases (MN) and oligonucleotide-directed mutagenesis (ODM) enabled a precise modification of DNA sequences in plants. Genome editing has already been applied in a wide range of plant species due to its simplicity, time saving and cost-effective application compared to earlier breeding techniques including classical mutagenesis. Although genome editing techniques induce much less unintended modifications in the genome (off-target effects) compared to classical mutagenesis techniques, off-target effects are a prominent point of criticism as they might cause genomic instability, cytotoxicity and cell death. Methods The aim of this systematic map is to address the following primary question: “What is the available evidence for the application of genome editing as a new tool for plant trait modification and the potential occurrence of associated off-target effects”? The primary question will be considered by two secondary questions: One is aimed at the traits being modified by genome editing in plants and the other explores the occurrence of off-target effects. The systematic map will focus on model plants as well as on plants produced for agricultural production that were subjected to genome editing techniques. Academic and grey literature will be searched in English and German language. Inclusion/exclusion criteria were developed for the two secondary questions and will be applied on title/abstract and full text stage. Included studies will be catalogued in a searchable and open access database and study results will be summarized using descriptive statistics. Furthermore, the extracted data will serve as a preparatory step for further in-depth analysis, e.g. by a systematic review.

Keywords

• New plant breeding techniques
• CRISPR/Cas
• TALENs
• Meganucleases
• Zinc-finger nucleases
• Oligonucleotide-directed mutagenesis