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Crop Biotech Update

CRISPR Nucleases Evaluated for Genome Editing in Maize

August 1, 2018

CRISPR-Cas9 and Cas12a (Cpf1) nucleases are two of the most powerful genome editing tools in plants. Iowa State University researchers compared the activities of these two nucleases by targeting the maize glossy2 gene coding region. The research team, led by Keunsub Lee, introduced the SpCas9‐guide RNA (gRNA) and LbCas12a‐CRISPR RNA (crRNA) into maize inbred embryos using Agrobacterium‐mediated transformation.

Analysis showed that 90-100% of the Cas9‐edited T0 plants carried mutations, 63-77% of which were homozygous or biallelic mutants. Meanwhile, 0-60% of Cas12a-edited T0 plants had the on-target mutations. Analysis of potential off-target sites for the two nucleases identified 18 and 67 potential off‐targets for SpCas9 and LbCas12a, respectively. Further analysis of the off‐target sites revealed no detectable mutations in the T1 plants.

These results suggest that the CRISPR-Cas9 system used in this study is highly efficient and specific for genome editing in maize. On the other hand, CRISPR-Cas12a needs to be improved for genome editing.

For more information, read the article in Plant Biotechnology Journal.