In Vitro Propagation via Organogenesis and Formation of Globular Bodies of Salvia Plebeia: A Valuable Medicinal Plant

Abstract

Background: As a highly valued medicinal plant, Salvia plebeia R. Brown belongs to the Lamiaceae family that has been subjected to over exploitation in its natural habitat for phytochemical and pharmacological studies. Alternative collection methods need to be developed for the large-scale propagation of Salvia plebeian. Results: Here, efficient and simple, direct organogenesis (from shoot tips and cotyledonary nodes explants) and Globular bodies (GBs) induction (from hypocotyl explants) systems were developed for the in vitro propagation of Salvia plebeia. The highest and number of regenerated shoots (7.0±0.82) per shoot tips was obtained on Murashige and Skoog (MS) medium supplemented with a combination of 0.1 mg L-1 indole-3-acetic acid (IAA) and 1.0 mg L-1 6-benzyladenine (6-BA), the proliferation of shoots and shoots rooted were carried out on the same medium treatments almost synchronously. Similarly, MS medium supplemented with 0.1 mg L-1 IAA and 1.0 mg L-1 thidiazuron (TDZ) yielded the maximum number of shoots (37.5±1.34) with 100% shoot sprouting frequency. Simultaneously, a protocol was developed for GBs induction from hypocotyl explants, and it produced 17.4 GBs per explant with 82.7% response on MS medium supplemented with TDZ (1.0 mg L-1) and IAA (0.1 mg L-1), and produced GBs that were morphologically similar to globular embryos and successfully germinated on hormone-free MS medium. The acclimatized plantlets with well-developed root systems were successfully shifted to the natural soils with a 100% survival rate. Conclusions: Taken together, this protocol can be efficiently used for mass propagation, germplasm preservation and likely also for gene transfer of Salvia plebeia.