Body of Abstract: The Scutellaria genus includes over 400 species with various medicinal values. In east Asia, Scutellaria baicalensis and Scutellaria barbata have been used to treat hepatitis, appendicitis, pain, and pulmonary abscess for thousand years. Recent studies have revealed that Scutellaria species are enriched with specialized metabolites, particularly deoxyflavones which are accumulated mainly in their roots and are responsible for their bioactive properties.
To improve pharmaceutical and therapeutic properties of Scutellaria, we attempted to engineer Scutellaria barbata genetically through Agrobacterium-mediated transformation by optimizing callus development, supplemental growth regulators, rooting and acclimatization. Rieske-type oxygenase (ObF8H) has been reported to function in flavonoid biosynthesis in sweet basil (Ocimum basilicum). We hypothesized that SbRTO a homologue of ObF8H in Scutellariabacalensis may be involved in flavone biosynthesis in Scutellaria. The coding region of SbRTO was cloned into a vector, pGWB442 harboring CaMV35S promoter, eYFP and Nos-terminator. The plasmids were delivered into the genome of S. barbata by Agrobacterium tumefaciens. We found out that combination of 2 mg×L-1 TDZ and 0.5 mg×L-1 NAA resulted in the best development of callus and shoot for regeneration of S. barbata. IBA (1 mg×L-1) was the most effective to initiate roots from shoots and activated charcoal (1%) added on rooting medium boosted the root development. YFP signals were detected from the calli developed onto selection medium containing kanamycin (25 mg×L-1) and roots developed from MS medium containing IBA and activated charcoal. Several transgenic lines were selected with confirmation of PCR amplification from genomic DNA. Also, we determined the changes of flavonoid profiles from the selected SbRTO-transgenic plants.