Establishment of a high frequency plant regeneration system of Rauvolfia verticillata via somatic embryogenesis

Rauvolfia verticillata is a traditional Chinese medicinal plant which contains a variety of terpenoid indole alkaloids such as ajmalicine, reserpine, rescinamine, serpentinine and yohmbine. The present investigation has successfully established the high frequency plant regeneration system of Rauvolfia verticillata via somatic embryogenesis. Leaves and stems were used as explants to induce calli on MS medium with 5 mg/L 2,4-D, 0.5 mg/L NAA, 0.2 mg/L 6-BA and half-strength MS medium supplemented with 0.8 mg/L IBA, respectively. Embryogenic cells emerged when sub-culturing calli induced from stems on MS medium supplemented with 2.0 mg/L 6-BA and 0.05 mg/L NAA, while calli initiated from leaves could not form embryogenic cells under the same condition. Embryogenic cells were separated from ordinary calli and propagated. After a sub-culturing period of 2 weeks on basic MS medium, shoots emerged on embryogenic cells and could root well on half-strength MS medium containing 0.8 mg/L IBA to become intact plants. Our present research laid basic foundation for improving yield of terpenoid indole alkaloid in R. verticillata by taking advantage of transgenic technology.