Triterpenoid production and phenotypic changes in hairy roots of Codonopsis lanceolata and the plants regenerated from them

Abstract

Codonopsis lanceolata (Campanulaceae) has been used in traditional medicines, as its roots contain several kinds of triterpenoid saponin with high medicinal values. In this work, we induced transgenic hairy roots of C. lanceolata and analyzed triterpenoid saponins from the hairy roots and hairy root-derived transgenic plants. Hairy roots were obtained from leaf explants by the transformation of Agrobacterium rhizogenes R1000. Transgenic hairy root lines were confirmed by the transcriptional activities of rolA, B, C, and D genes by RT-PCR. Transgenic root lines actively proliferated on hormone-free medium but not in nontransformed roots. Hairy roots contained richer triterpenoids (lancemaside A, foetidissimoside A, and aster saponin Hb) than nontransformed roots. Transgenic plants were regenerated from the hairy roots via somatic embryogenesis. They showed phenotypic alterations such as shortened shoots and an increased number of axillary buds and adventitious roots. The transgenic plants also contained higher triterpenoid levels than wild-type plants. These results suggest that hairy roots and transgenic plants of C. lanceolata could be used as medicinal materials for the production of triterpene saponins.