Two different agropine strains (A4T and LBA 9402) of Agrobacterium rhizogenes were tested for their capacity to induce hairy roots on Salvia runcinata L. f. explants. Both nodal and leaf explants were examined and hairy roots formed 3 to 4 weeks after inoculation. Although the LBA 9402 strain produced significantly more roots on each explant compared with the A4T strains, at the time of transformation, stable cultures could only be established using the A4T strain at a frequency of 4.17%. Putative transgenic roots exhibited a faster growth pattern when compared with wildtype roots. Out of the roots established, we continued the study with two clones that showed typical features of the hairy root syndrome. Amplification of the rol A, rol B, rol C and ags gene (showing 300, 400, 600 and 1600 bp bands after electrophoresis, respectively) was positive using the polymerase chain reaction (PCR) and reverse-transcriptase-polymerase chain reaction (RT-PCR). Moderate antifungal activity against two Fusarium strains was exhibited by extracts generated from transgenic clones. We were also able to show the presence of some caffeic acid metabolites. These biochemicals are known to exhibit various biological activities, and therefore, the transgenic hairy roots of S. runcinata may be an alternative source of these industrially useful chemicals.
Figlan, S., & Makunga, N. P. (2017). Genetic transformation of the medicinal plant Salvia runcinata L. f. using Agrobacterium rhizogenes. South African Journal of Botany, 112, 193–202. https://doi.org/10.1016/j.sajb.2017.05.029