Hairy root cultures of Salvia viridis L. for production of polyphenolic compounds

Salvia viridis is a containing bioactive phenols plant, which has been used in Turkish medicine. The aim of the study was to establish hairy root culture of the species in order to increase the production of the compounds with pharmacological activity. Transformed roots are promising biotechnological systems that produce great amounts of secondary metabolites; this is attributed to their fast growth and their genetic and biosynthetic stability. Stable hairy root lines of S. viridis were established from shoot explants using Agrobacterium rhizogenes strain A4. The highest frequency of transformation (45%) was achieved when the shoot was inoculated at the node or internode by bacteria cultivated on Yeast/Mannitol/Broth (YMB) medium supplemented with acetosyringone. The transformation of the root clones was confirmed by polymerase chain reaction using auxl, aux2, rolB and rolC primers. Of the five obtained transformed root clones, the highest biomass was achieved for clone K3 (13.63 +/- 0.5 g/L after 5 weeks) grown in Woody Plant (WP) medium in darkness. The UPLC-PDA-ESI-MS analysis of hydromethanolic extracts of transformed roots of S. viridis revealed the presence of 10 compounds identified as caffeic acid derivatives. Quantitative analysis showed that rosmarinic acid (RA) was the predominant compound in all clones. The highest RA (35.8 mg/g dry weight) and total polyphenol (41.24 mg/g dry weight) content were evaluated in clone K3 cultured in WP medium. These values were 8-fold higher than those of the non-transformed roots, indicating that hairy root cultivation could be a promising technique for the production of valuable compounds from S. viridis.