Hairy root cultures of Physalis minima L. ? an alternative source of withaferin A production

Physalis minima L. is an important yet underutilised medicinal plant. It has many medicinal properties, including anticancer activity. This plant synthesizes a crucial steroidal lactone, withaferin A, with high medicinal value in addition to a number of alkaloids, steroids and phenolic compounds. We have established, for the first time, the hairy root culture (HRC) of this plant via explant cocultivation with the wild-type A4 strain of Agrobacterium rhizogenes to increase the production of the high-value steroidal lactone withaferin A. A maximum transformation efficiency of 83.49 +/- 2.45% was recorded with acetosyringone-treated (200 mu M) bacterial culture. Genetic transformation was confirmed using primers specific to seven different genes. After screening several HR lines, five lines were selected based on their increased growth rate and high accumulation of withaferin A. Elicitation was applied to high-yielding root lines to further enhance the withaferin A accumulation. The effects of two biotic (chitosan and yeast extract) and three abiotic (salicylic acid, methyl jasmonate and aluminium chloride) elicitors on withaferin A accumulation were studied at different concentrations. While all the elicitors effectively increased withaferin A production, salicylic acid (4.14 mg l(-1)) induced an approximately 21-fold increase in withaferin A accumulation (19.081 +/- 0.058 mg g(- 1) DW) after 4 d of elicitation compared to the nonelicited culture (0.892 +/- 0.037 mg g(- 1) DW). These results suggest that the use of elicitors can tremendously increase the biosynthesis of withaferin A in this system; thus, the HRs of P. minima can be explored in the future for enhanced production of withaferin A. Key message Establishment of the hairy root culture of Physalis minima L. for the production of withaferin A and evaluation of its production in elicitor-treated, high yielding hairy root line.