Peculiarities of diterpenoid steviol glycoside production in in vitro cultures of Stevia rebaudiana Bertoni

The composition and content of steviol-glycosides (SGs)(1) in in vitro cultures of stevia (Stevia rebaudiana Bertoni) were investigated. A comparative analysis of production of these compounds in intact plants, in vitro plants, dedifferentiated callus and suspension cultures, morphogenic callus and in vitro regenerated shoots were conducted. Qualitative composition of the SGs in in vitro plants was found to be identical to that of intact plants, but their content in the former plants appeared to be about five or six times lower. A significant decrease in this value was not observed upon long-term cultivation (for about 5 years) of the plants. Non-differentiated cell cultures, such as callus and cell suspension, were shown to synthesize only minor amounts of the SGs, and their content varied greatly during the growth cycle of the culture. Qualitative composition of the SGs in the cell cultures appeared to be highly scant as compared with that of the donor plants. No correlation between the SG content in organs of the donor plants and that in the cell cultures obtained was found. Factors determining plant cultivation conditions and influencing the accumulation of both, fresh and dry cell biomass were not able to completely induce the SG synthesis in non-differentiated cell cultures. This process was found to be restored only after the appearance of morphogenic structures and shoot formation. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.