Elicitor-induced phenolic acids accumulation in Salvia virgata Jacq. hairy root cultures

Abstract Phenolic acids, as the predominant secondary metabolites of Salvia species, are largely used in pharmaceutical industries. The main aim of the study was to establish hairy root cultures of Salvia virgata Jacq. Also, the effects of methyl jasmonate (22.4 and 11.2 ppm), Ag+ ions (5 and 2.5 ppm), and yeast extract (100 and 50 ppm) were assessed on total phenol, total flavonoid, rosmarinic acid, salvianolic acid A, and caffeic acid contents in the hairy roots after 1, 3 and 5 days of exposure. Results showed the used Agrobacterium rhizogenes strains (A4, ATCC15834, R1000, GM1534, and C58C1) differed in their ability to induce hairy roots on leaf explants. The transformed roots were molecularly confirmed using rolC gene and the highest transformation frequency (56 %) was obtained by ATCC 15834 strain. Among the established hairy root lines, the highest amount of rosmarinic acid (0.45 ± 0.01 mg/g DW) and dry root biomass (2.29 ± 0.04 g) was obtained in AT3, the line which was induced by ATCC 15834 strain. The maximum accumulation of total phenol (123.6 ± 0.93 mg GAE/g DW), total flavonoid (5.09 ± 0.07 mg QUE/g DW), rosmarinic acid (18.45 ± 0.8 mg/g DW), salvianolic acid A (2.11 ± 0.04 mg/g DW) and caffeic acid (2.61 ± 0.02 mg/g DW) was observed in the hairy roots elicited with 22.4 ppm methyl jasmonate on day three after treatment. The results support that elicitation could be an effective procedure for the improvement of caffeic acid derivatives production in S. virgata hairy root cultures.