Indole alkaloid accumulation and tryptophan decarboxylase activity in Catharanthus roseus cells cultured in three different media

Abstract

Catharanthus roseus cells were cultured in three types of media. These media were: a low sucrose subculture medium and two high sucrose media, each of which differed in their mineral and hormonal contents. The kinetics of tryptophan decarboxylase activity and the accumulations of tryptophan, tryptamine, ajmalicine and serpentine were different in each series but no correlation between maximum enzyme activity and alkaloid contents was observed. Ajmalicine and serpentine productions were unaffected by addition of Trp to the media, whereas addition of secologanin enhanced alkaloid production. The results seem to imply that the terpenoid pathway is the limiting factor in alkaloid production in C. roseus cells.

Expression of a 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase Gene from Camptotheca acuminata Is Differentially Regulated by Wounding and Methyl Jasmonate

“…Feeding experiments with C. m e u s tissue cultures suggest that terpenoid synthesis may represent the limiting step in indole alkaloid production (Merillon et al, 1986(Merillon et al, , 1989; therefore, it is of interest to begin to dissect the regulation of this portion of the pathway.…”

Indole Alkaloid Production in Catharanthus roseus Cell Suspension Cultures

“…The reports in the literature concerning the effects of precursors on alkaloid production are contradictory. Thus, adding tryptamine (46) or tryptophan or both to the medium has occasioned different responses in cells, in some cases stimulation of alkaloid production (16,46) and in others repression (79) or no change (80). The results were negative when cells were stimulated to overproduce these precursors.…”

“…Addition of precursors of the terpenoid pathway (e.g. loganin, secologanin (47» in some cases increased alkaloid levels (16,80), but in other cases effects were insignificant (83) or inhibitory (16).…”

“…Clearly no generalization of the positive or negative effects of any given precursors should be claimed unless the strains (46) and the culture parameters (80) are exactly defined and characterized.…”

Cloning of a cDNA encoding an E2 ubiquitin‐conjugating enzyme from Catharanthus roseus : expression analysis in plant organs and in response to hormones in cell suspensions

“…E2 conjugating enzymes function by accepting activated ubiquitin from ubiquitin activating enzymes (E1s) and transferring it to a target protein. In Catharanthus roseus cell suspension cultures, the biosynthesis of valuable terpenic indole alkaloids (TIA) is down-regulated by auxin and up-regulated by MeJa and by the anti-senescent hormone cytokinin (Gantet et al, 1998;Mérillon et al, 1986). TIA are biosynthesized from strictosidine, the product of the condensation of tryptamine and secologanin by strictosidine synthase (STR).…”