Researchers Use CRISPR/Cas9 for Precise Excision of Transgenes from Rice Genome

The CRISPR/Cas9 system has emerged as a versatile gene editing tool that functions through the double-stranded break repair leading to targeted mutagenesis. This RNA-guided nuclease system has mostly been applied for inducing point mutations or short insertion-deletions at one or multiple loci.

Researchers from University of Arkansas, led by Vibha Srivastava, used CRISPR/Cas9 system for excising marker genes from plant genomes to develop marker-free transgenic plants. A transgenic rice line expressing β-glucuronidase (GUS) gene was transformed by Agrobacterium or gene gun with a construct expressing Cas9 and two guide RNAs to target each end of the GUS gene.

Analysis of the transformed lines detected excision at low frequency in the callus lines. However, a significantly higher excision frequency was detected in plant lines, indicating the efficiency of Cas9:gRNA in regenerated plants.

Marker-removal technologies aim to precisely excise a specific piece of DNA without introducing mutations, and the Cas9:gRNA system could be an effective tool for producing marker-free plants.

For more on the study, read the article in Plant Cell, Tissue and Organ Culture.