Carbohydrate and elicitor enhanced withanolide (withaferin A and withanolide A) accumulation in hairy root cultures of Withania somnifera (L.).

ABSTRACT

Leaves of Withania somnifera contained more withaferin A and withanolide A than roots indicating that these compounds mainly accumulate in leaves. With an increase in age of the plant, withaferin A was enhanced with a corresponding decrease in withanolide A. Hairy root cultures were induced from leaf explants using Agrobacterium rhizogenes and the transgenic nature of hairy roots was confirmed by partial isolation and sequencing of rolB gene, which could not be amplified in untransformed plant parts. In hairy roots, withaferin A accumulated at 2, 3 and 4% but not at 6% sucrose, the highest amount being 1733 mg/g dry weight at 4% level. High and equal amounts of withaferin A and withanolide A accumulated (890 and 886 mg/g dry tissue respectively) only at 3% sucrose. Increasing concentrations of glucose enhanced withaferin A and it peaked at 5% level (3866 mg/g dry tissue). This amount is 2842 and 34% higher compared to untransformed roots and leaves (collected from 210-day-old plants) respectively. Withanolide A was detected at 5% glucose but not at other concentrations. While chitosan and nitric oxide increased withaferin A, jasmonic acid decreased it. Acetyl salicylic acid stimulated accumulation of both withaferin A and withanolide A at higher concentrations. Triadimefon, a fungicide, enhanced withaferin A by 1626 and 3061% (not detected earlier) compared to hairy and intact roots respectively.