Effects of biotic elisitor applications on root growth and alkaloid production in Isatis tinctoria L. root cultures

This study was carried out to determine the effects of yeast extract, chitosan and pectin on the root growth and the accumulation of indigotin and indirubin, the most important indole alkaloids of the plant, in the root of Isatis tinctoia (woad). in in vitro conditions. For this purpose, different concentrations of yeast extract (1, 2, 3 and 4 g/l), chitosan (100, 150, 200 and 250 mg/l), and pectin (0.5, 1, 2 and 3%) were applied to 21 days old roots for 7 days. After harvest, roots were evaluated in terms of fresh root weight, root growth index, dry root weight and contents of indigotin and indirubin. As a result of the study, it was determined that yeast extract showed positive effects on root growth while chitosan inhibited. On the other hand pectin had no positive or negative effects on root growth parameters. Yeast extract and chitosan applications increased indigotin accumulation in roots compared to control roots while indigotin amounts decreased with the pectin application. Within yeast extract applications, the highest indirubin contents were obtained from the roots applied with 3 and 4 g/l of yeast extract. All chitosan application enhanced the indirubin accumulation compared to control. The effect of pectin applications on indirubin accumulation was changed depending on its concentrations. Pectin at 0.5 and 1% increased indirubin contents compared to control and other pectin concentrations. As a conclusion, 1 g/l of yeast extract for root growth and 100 mg/l of chitosan for indigotin and indirubin contents were selected the most appropriate applications suppling the highest values.