The CRISPR-Cas9 system is a powerful genome editing tool that has been used in many species. However, it has never been applied on red sage (Salvia miltiorrhiza), a traditional Chinese medicinal herb. To test the CRISPR-Cas9 system’s applicability in red sage, the team of Zheng Zhou from the Second Military Medical University in China focused on its rosmarinic acid synthase gene (SmRAS) of red sage.
A single guide RNA (sgRNA) was designed to edit the SmRAS gene. Five biallelic mutants, two heterozygous mutants and one homozygous mutant were obtained. Analysis showed that the contents of phenolic acids, including rosmarinic acid, and the expression level of SmRAS were decreased in the successfully edited lines, particularly in the homozygous mutants. Furthermore, the level of the rosmarinic acid precursor clearly increased.
These results indicate that the CRISPR-Cas9 system can be used to identify important genes and that this technology is an efficient tool for genome editing in red sage. This system presents a promising potential method to improve the quality of traditional Chinese medicinal herbs.