Highly Efficient CRISPR-Associated Protein 9 Ribonucleoprotein-Based Genome Editing in Euglena gracilis

Euglena gracilis, a unicellular phytoflagellate microalga, is a promising biomaterial for foods, feeds, and biofuels. However, targeted mutagenesis in this species has been a long-standing challenge. We recently developed a transgene-free, highly efficient, genome editing method for E. gracilis using CRISPR/Cas9 ribonucleoproteins (RNPs). Our method achieved mutagenesis rates of approximately 80% or more through an electroporation-based direct delivery of Cas9 RNPs. Therefore, this method is suitable for basic research and industrial applications, such as the breeding of Euglena. For complete details on the use and execution of this protocol, please refer to Nomura et al. (2019).