One-Step Regeneration of Hairy Roots to Induce High Tanshinone Plants in Salvia miltiorrhiza.

Salvia miltiorrhiza is a traditional Chinese medicinal plant of Labiatae, which has been widely utilized to treat a variety of cardiovascular and cerebrovascular diseases. However, due to the long growth cycle, low content of active ingredients, and serious quality deterioration of S. miltiorrhiza, the use of biotechnology to improve S. miltiorrhiza to meet the growing demand for clinical applications has become a research hotspot. In this study, a novel one-step hairy root regeneration method was developed, which could rapidly obtain hairy roots and regenerated plants with high tanshinone content. By optimizing the parameters of Agrobacterium rhizogenes transformation in S. miltiorrhiza, it was finally established that the explants were infected in Ar.qual (OD600 = 0.6) for 10 min, co-cultured for 3 days, and then screened on the screening medium containing 7.5 mg/l hygromycin, the maximum transformation frequency can reach 73.85%. GFP and PCR detection yielded a total of 9 positive transgenic hairy root lines and 11 positive transgenic regenerated plants. SmGGPPS1 was successfully overexpressed in positive transgenic regenerated plants, according to the results of qRT-PCR. The content of tanshinone IIA and cryptotanshinone were dramatically enhanced in transgenic regenerated plants and hairy roots by Ultra Performance Liquid Chromatography analysis. Based on the Agrobacterium-mediated transformation of S. miltiorrhiza, this study developed a new method for regenerating plants with transgenic hairy roots. This method provides a foundation for the breeding of S. miltiorrhiza and the sustainable development of medicinal plant resources, as well as provides a useful reference for the application of other species.

[Directing construction of CRISPR/Cas9 vector of SmPAL1 in Salvia miltiorrhiza by target efficiency detection in vitro].

To construct CRISPR/Cas9 vectors for the editing of SmPAL1 in the phenylpropane metabolic pathway of Salvia miltiorrhiza, CIRSPR/Cas9 target sites of SmPAL1 were designed by online software. Its target efficiencies were detected in vitro by enzyme digestion and sequences with highly efficiency were constructed into CRISPR/Cas9 vectors. Three possible CRISPR target sequences (SmPAL1-g1, SmPAL1-g2, SmPAL1-g3) were designed and the enzyme digestion efficiencies were 53.3%, 76.6% and 10.0%. SmPAL1-g1 and SmPAL1-g2 were constructed into vector VK005-03 named as VK005-03-g1 and VK005-03-g2. The results of sequencing showed that the two CRISPR/Cas target sequences were all constructed into VK005-03. Here we first laid the foundation for the study of SmPAL1 and provided an effective strategy for the screening of sgRNA.