Metabolic engineering of the indole pathway in Catharanthus roseus hairy roots and increased accumulation of tryptamine and serpentine.

Transgenic hairy roots of Catharanthus roseus were established with glucocorticoid inducible tryptophan decarboxylase (TDC) expression alone or in combination with inducible expression of a feedback-resistant anthranilate synthase alpha subunit (ASalpha) from Arabidopsis. Northern blot analysis confirmed transcription of the anthranilate synthase gene upon induction in the double line (TDC+ASalpha) and in vitro enzyme assays confirmed increased resistance to feedback inhibition by tryptophan. In TDC enzyme assays, increases of 48% and 87% in the TDC and double lines, respectively, were noted.