Transient induction of tryptophan decarboxylase (TDC) and strictosidine synthase (SS) genes in cell suspension cultures of Catharanthus roseus.

When cell suspension cultures of Catharanthus roseus are treated with autoclaved elicitor from the fungus Pythium aphanidermatum, they respond with the rapid transient induction of tryptophan decarboxylase (TDC) and strictosidine synthase (SS) enzyme activities, followed by the accumulation of indole alkaloids (Eilert et al., 1987). In this report, we demonstrate that expression of TDC and SS enzyme activities is preceeded by the transient appearance of mRNAs for both enzymes, suggesting transcriptional control of these events. The strong transient accumulation of both TDC and SS enzyme transcripts observed in elicitor-treated cell suspension cultures contrasts with the barely detectable level of TDC transcripts and the undetectable level of SS transcripts observed in developing seedlings.