Propagation of Salvia miltiorrhiza from hairy root explants via somatic embryogenesis and tanshinone content in obtained plants

An effective protocol for plant regeneration from hairy root (HR) via indirect somatic embryogenesis was established in medicinal plant Salvia miltiorrhiza. On the MS medium with 1.0 mgl(-1) 2, 4-dichlorophenoxyacetic (2,4-D) and 0.5 mgl(-1) 6-benzylaminopurine (6-BA), the hairy root explants produced embryogenic callus. After transferred to the MS medium with 0.05 mgl(-1) alpha-naphthylacetic acid (NAA) and 0.5 mgl(-1) 6-BA, the embryogenic callus produced cotyledonary somatic embryo and developed into plantlets. PCR analyses revealed plants regenerated from HRs (HR-plants) retained rolA, B, C and D genes. Morphologically, HR-plants displayed wrinkled leaves, longer and thickened taproots. The biomass of roots and shoots of HR-plants increased by 2.7- and 1.5-fold, respectively, and the total content of tanshinones in their roots raised by 79.5%, in comparison with wild type (WT)-plants. The gene expression of 3-hydroxy-3-methylglutaryl CoA redutase (HMGR) and 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR), the first two key enzymes in the pathway of tanshinone synthesis, was up-regulated in roots of HR-plants. This study offers an effective breeding method and material for producing tanshinones. (C) 2013 Elsevier B.V. All rights reserved.