The Catharanthus alkaloids: pharmacognosy and biotechnology.

The Catharanthus (or Vinca) alkaloids comprise a group of about 130 terpenoid indole alkaloids. Vinblastine is now marketed for more than 40 years as an anticancer drug and became a true lead compound for drug development. Due to the pharmaceutical importance and the low content in the plant of vinblastine and the related alkaloid vincristine, Catharanthus roseus became one of the best-studied medicinal plants.

Identification of UV-B light-responsive regions in the promoter of the tryptophan decarboxylase gene from Catharanthus roseus.

The tryptophan decarboxylase (Tdc) gene encodes a key enzyme in the biosynthesis of terpenoid indole alkaloids (TIAs) in Catharanthus roseus. TIAs absorb ultraviolet light (UV) and putative functions in plants include a role as UV protectants. In support of this possible function we demonstrate here that UV light induces accumulation of several TIAs as well as expression of the Tdc gene in C.

Alkaloid production by a Cinchona officinalis 'Ledgeriana' hairy root culture containing constitutive expression constructs of tryptophan decarboxylase and strictosidine synthase cDNAs from Catharanthus roseus.

 Cinchona officinalis 'Ledgeriana', former called Cinchona ledgeriana, hairy roots were initiated containing constitutive-expression constructs of cDNAs encoding the enzymes tryptophan decarboxylase (TDC) and strictosidine synthase (STR) from Catharanthus roseus, two key enzymes in terpenoid indole and quinoline alkaloid biosynthesis. The successful integration of these genes and the reporter gene gus-int was demonstrated using Southern blotting and the polymerase chain reaction. The products of TDC and STR, tryptamine and strictosidine, were found in high amounts, 1200 and 1950 μg g dry weight, respectively.

Expression of two consecutive genes of a secondary metabolic pathway in transgenic tobacco: molecular diversity influences levels of expression and product accumulation.

We have created a population of transgenic tobacco plants carrying cDNAs encoding two consecutive enzymes from early stages in monoterpenoid alkaloid biosynthesis in Catharanthus roseus. The cDNAs, encoding tryptophan decarboxylase (tdc) and strictosidine synthase (str1) together with a selectable marker gene, were introduced on a single transforming plasmid into tobacco leaves by particle bombardment. Analysis of 150 independent transgenic plants at the DNA and RNA levels demonstrated a range of integration events and steady-state transcript levels for the tdc and str1 transgenes.

Influence of Precursor Availability on Alkaloid Accumulation by Transgenic Cell Line of Catharanthus roseus.

We have used a transgenic cell line of Catharanthus roseus (L.) G. Don to study the relative importance of the supply of biosynthetic precursors for the synthesis of terpenoid indole alkaloids.