Boosting Rice Genome Editing with New Cas9 Variants

Scientists have discovered a new way to make genome editing more efficient in rice. A protein called ScCas9, which comes from bacteria, can recognize a wider range of targets in the DNA than the commonly used protein, SpCas9. However, both ScCas9 and its improved version, Sc++, still don't work very well in plants, especially for certain DNA sequences like NTG and NCG. To fix this, researchers created a new protein called SpcRN++. They combined parts of SpCas9 and another bacterial protein, S. anginosus Cas9, and added some specific changes. SpcRN++ can edit the genome more effectively and target a wider range of DNA sequences in rice. What's more, when scientists used SpcRN++ with other editing tools, like A3A and TadA8e, they saw even better results. They could edit more cytosine and adenine bases in the DNA. Finally, they created herbicide-resistant rice by targeting a specific gene, OsACC, using SpcRN++. These findings show that SpcRN++ is a powerful tool for editing plant genomes. The method used to create it could also help improve other Cas9 proteins in the future.