Effect of Elicitor Dosage and Exposure Time on Biosynthesis of Indole Alkaloids by Catharanthus roseus Hairy Root Cultures

Abstract

Late exponential phase hairy root cultures of Catharanthus roseus were elicited with pectinase and jasmonic acid. The effects of elicitor concentration and exposure time on growth and levels of several compounds in the indole alkaloid biosynthetic pathway were monitored. Pectinase decreased the fresh weight to dry weight ratio of the roots, while addition of jasmonic acid had no significant effect. Selective effects on indole alkaloid yields were observed upon addition of elicitors. An increase of 150% in tabersonine specific yield was observed upon addition of 72 units of pectinase. Transient studies at the same level demonstrated possible catabolism as serpentine, tabersonine, and lochnericine levels decreased immediately after elicitation. The levels of these compounds recovered back to control levels or were higher than the control levels after some time. Jasmonic acid was found to be a unique elicitor leading to an enhancement in flux to several branches in the indole alkaloid pathway. Jasmonic acid addition caused an increase in the specific yields of ajmalicine (80%), serpentine (60%), lochnericine (150%), and hörhammericine (500%) in dosage studies. Tabersonine, the likely precursor of lochnericine and hörhammericine, decreased at lower levels of jasmonic acid and then increased with increasing jasmonic acid concentration. Transient studies showed that lochnericine and tabersonine levels go through a maxima, then decrease back to control levels and reduce below control levels, respectively. The yields of ajmalicine, serpentine, and hörhammericine increased continuously after the addition of jasmonic acid. The methods described in this article could generally be used in devising strategies for enhancement in productivity of secondary metabolites and for probing and studying the complex secondary metabolite pathways in plant tissue cultures.

Metabolic alterations and distribution of five-carbon precursors in jasmonic acid-elicited Catharanthus roseus cell suspension cultures

“…In the elicitation process, jasmonates play an important role as regulatory signals to induce de novo transcription and translation leading to the induction of secondary metabolite biosynthesis in plant cell cultures Zhao and Verpoorte 2007). Exogenous application of jasmonates to C. roseus cell cultures (El-Sayed and Verpoorte 2002; Lee-Parsons and Royce 2006;Vázquez-Flota et al 2009), hairy roots (Rijhwani and Shanks 1998;Vázquez-Flota et al 2009), shoot cultures (Vázquez-Flota et al 2009) and seedlings (ElSayed and Verpoorte 2004) increased the production of TIA caused by an elevated expression of a set of biosynthesis related genes . Combination of transcript and metabolic profiling of jasmonate elicited C. roseus cell cultures yielded a collection of known and previously undescribed transcript tags and metabolites associated with TIA (Rischer et al 2006).…”

Microbial synthetic biology for human therapeutics

“…Second, there are several plant species which are not amenable to micropropagation and hence rendered recalcitrant to plant tissue culture techniques. Third, for plants such as Catharanthus roseus, a well known source of anticancerous agents (vincristine and vinblastine), the ultimate objective of obtaining high yields of the medicinally active compound is not achieved since the active compound is either not produced or produced in even lesser amounts as compared to its wild-type form via micropropagation (Rijhwani and Shanks 1998).…”

The effects of elicitation on the expression of key enzyme genes and on production of tropane alkaloids in Anisodus acutangulus plant

“…Methyl jasmonate (MJ) was reported to be a signaling molecule in biotic and abiotic stresses (Zhao et al 2005;Arias Zabala et al 2010). Lots of experiments have demonstrated that MJ was able to stimulate the production of several compounds in many species (Ignatov et al 1996;Rijhwani & Shaks 1998;Dong & Zhong 2002;Wang & Zhong 2002;Vasconsuelo & Boland 2007). Yeast extract (YE), a kind of polysaccharide, was also been reported to have the ability to regulate increase or decrease different secondary metabolites in many species, such as syringin, valeportriates, podophyllotoxin and silymarin (Kittipongpatana et al 2002;Shams-Ardakani et al 2005;Xu et al 2007;Hasanloo et al 2009).…”