Development of a Genome Editing Technique Using the CRISPR/Cas9 System in the Industrial Filamentous Fungus Aspergillus Oryzae

Objectives: To develop a genome editing method using the CRISPR/Cas9 system in Aspergillus oryzae, the industrial filamentous fungus used in Japanese traditional fermentation and for the production of enzymes and heterologous proteins.

Results: To develop the CRISPR/Cas9 system as a genome editing technique for A. oryzae, we constructed plasmids expressing the gene encoding Cas9 nuclease and single guide RNAs for the mutagenesis of target genes. We introduced these into an A. oryzae strain and obtained transformants containing mutations within each target gene that exhibited expected phenotypes. The mutational rates ranged from 10 to 20 %, and 1 bp deletions or insertions were the most commonly induced mutations.

Conclusions: We developed a functional and versatile genome editing method using the CRISPR/Cas9 system in A. oryzae. This technique will contribute to the use of efficient targeted mutagenesis in many A. oryzae industrial strains.