4.4.1. In vitro production
Compact callus cells feeding with tryptamine, succinic acid, and tryptophan increased the terpene indole alkaloids production 3-5 fold. Hairy root culture of C. roseus fed with precursors (geraniol and nitroprusside) (Li et al., 2011; Morgan and Shanks, 2000) and immobilized cells techniques with high cell density did not increase terpene indole alkaloids (TIA) production in shoot and callus cultures as compared to control (Zhao et al., 2001). Suspension culture elicited with malate and sodium alginate proved to increase three-fold production of terpene indole alkaloids (ajmalicine and catharanthine) (Almagro et al., 2011).
In suspension culture of C. roseus , overexpression of strictosidine synthases (STR) and tryptophan decarboxylase (TDC) gene with the feeding of loganin and secologanin showed remarkable production by 24 fold (Whitmer et al., 2002). Elicitation studies also demonstrated that methyl jasmonate (MeJA) alone (Zhou et al., 2010) and/or in combination with another cyclodextrin could improve the output of catharanthine, one of the two precursors of the anticancer compound vinblastine, in C. roseus hairy roots through the enhanced expression of pathway genes (Almagro et al., 2014). UV-B light stress has been used as an elicitor to enhance TIAs, including vincristine and vinblastine production in C. roseus hairy roots (Lalaleo et al., 2016).