Enhancement of secondary metabolite production in hairy root cultures of Beta vulgaris and Tagetes patula under the influence of microalgal elicitors

The effect of aqueous extracts of green alga-Haematococcus pluvialis and bl ue green alga-Spirulina platensis was studied for accumulation of betalaine s (food colourant) and thiophenes (insecticide useful against food grain sp oilage) in hairy root cultures of Beta vulgaris and Tagetes patula, respect ively. It was found that upon treatment with extracts (100 mug dry cell ext ract/ml of the culture medium each) of H. pluvialis and S. platensis there was an increase in biomass of cultured Beta vulgaris hairy roots which was 165.3 g fresh wt/L (14.38 g dry wt/L) and 149.4 g fresh wt/L (13 g dry wt/L ), respectively from the initial inoculum of 1.25 g fresh wt/L (0.115 g dry wt/L). The accumulation of betalaines showed an increase of 2.28 fold on 1 5th day in hairy root culture treated with H. pluvialis over the control (7 .9 mg/g dry wt) on the same day from the initial level of 0.67 mg/g dry wt. Similarly S. platensis extract treated hairy roots showed elicitation of b etalaines 1.16 fold on 25th day over the control (11.08 mg/g dry wt) from t he initial level of 0.67 mg/g dry wt. It was also observed that the H. pluv ialis extract also influenced the biomass production in T. patula hairy roo ts which was 1.4 fold higher than the control (40 g fresh wt/L or 3.21 g dr y wt/L) on 20th day from the initial inoculum of 1.25 g fresh wt/L (0.105 g dry wt/L). Whereas the accumulation of thiophene increased by 1.2 fold in cultures treated with H. pluvialis extract on the 20th day over the untreat ed control (510 mug/g dry wet) from the initial level of 200 mug/g dry wt., while S. platensis extract did not influence the growth as well as thiophe ne accumulation. In conclusion S. platensis extract influenced elicitation of betalaines in B. vulgaris hairy roots where as H. pluvialis extract elic ited betalaine and thiophene production in hairy root cultures of B. vulgar is and T. patula respectively.