The Influence of Yeast Extract on the Production of Flavonolignans in Hairy Root Cultures of Silybum marianum L. Gaertn

Hairy roots cultures of Silybum marianum produce silymarin. In an attempt to increase productivity, the effect of yeast extract was tested. The hairy roots induced by inoculation of explants with A. rhizogenes (AR15834). One month old hairy roots were dissected from the explants and growth in the Erlenmeyer flask containing 50 ml MS liquid medium. PCR analysis using rolb gene and GUS assay were used for identification of transformed hairy roots. The presences of flavonolignans in the hairy roots were determined by high-performance liquid chromatography (HPLC). There were five isolated components; taxifolin, silychristin, silydianin, silybin and isosilybin and the major flavonolignan was silybin that has not been reported in previous published work. For increasing the growth rate of hairy roots, effects of NAA, IBA and IAA (0.1, 0.5 and 1 mg l(-1)) were tested. The best media was achieved by 0.5 mg l(-1) NAA. Elicitation was carried out with yeast extract (0, 0.5, 1, 2.5 and 5 mg ml(-1)) and different exposure times (24, 48 and 72 h). The highest silymarin content (0.476 mg g(-1) DW) was obtained by 2.5 mg ml(-1) yeast extract, after 72 h. This study indicates that elicitor treatment promotes silymarin production in hairy root culture of S.marianum.