Transient studies of nutrient uptake, growth, and indole alkaloid accumulation in heterotrophic cultures of hairy roots ofCatharanthus roseus

Abstract

The kinetics of growth, the uptake of macronutrients, and the accumulation of indole alkaloids were investigated in long-term, heterotrophically cultured transgenic (''hairy'') roots of Catharanthus roseus. Tabersonine, ajmalicine, and serpentine were monitored over a 70-day period. The doubling time [dry-weight (DW) basis] of C. roseus hairy roots in B5/2 nutrients supplemented with 3% sucrose was 3.6 days. NH 4 + , NO 3 , − and P i were depleted sequentially from culture medium by hairy roots, while sugars remained undepleted. The growth-limiting nutrient was inorganic nitrogen, NH 4 + and NO 3 − , with exponential-phase overall biomass yields of 34.1 and 5.0 g DW/g nutrient, respectively. Extracellular pH decreased to 4.8 in early exponential phase of culture growth from the initially adjusted value of 5.7, increased subsequently to a maximum of 7.7 in late exponential phase of growth coincident with the maximum of fresh weight (FW)/DW ratio, before decreasing to 5.5-5.0. The organic acids, pyruvate, formate, lactate, and succinate were excreted by hairy roots starting in late phase of exponential growth, possibly resulting in the late-culture pH decrease. Tabersonine accumulation was distinctly growth associated with maximum specific and total yields of 1.15 mg/g DW and 5.6 mg/L, respectively, in late-exponential phase of growth. Serpentine accumulation was non-growth associated with increasing specific and total levels in stationary growth phase: 1.3 mg/g DW and 10.5 mg/L, respectively. The accumulation of ajmalicine also appeared growth associated.

Hairy Root Cultures of Gynostemma pentaphyllum (Thunb.) Makino: A Promising Approach for the Production of Gypenosides as an Alternative of Ginseng Saponins

“…The result in this study closely resembles that for hairy roots of the Solanum aviculare (Subroto & Doran 1994) and Catharanthus roseus (Bhadra & Shanks 1997), indicating that the biosynthesis of gypenosides in G. pentaphyllum hairy roots occurred simultaneously with the biosynthesis of other primary metabolites used for growth. This pattern differs from the production behavior of most secondary metabolites, which showing that significant levels of production are observed after growth ceases (Payne et al 1992).…”

Sennosides A and B Production by Hairy Roots of Senna alata (L.) Roxb.

“…This evidence suggests that the biosynthesis of secondary metabolite increased during the stationary phase of growth. Similar observations have been noted for other hairy root cultures (Bhadra and Shanks, 1997;Merkli et al, 1997;Sasaki et al, 1998;Kittipongpatana et al, 2002). Increased production of secondary metabolite at the stationary phase might be come from the stress of tissue due to the change of environment such as undernourishment.…”

Enhanced accumulation of catharanthine and vindoline in Catharanthus roseus hairy roots by overexpression of transcriptional factor ORCA2

“…Therefore, many cell and hairy root cultures produce catharanthine and tabersonine, but do not produce vindoline because there is a limitation in the conversion from tabersonine to vindoline (Shanks et al, 1998). This fact had been confirmed by some experiments (Bhadra and Shanks, 1997;Brillanceau et al, 1989;Toivonen et al, 1989).…”