Affecting Secondary Product Formation in Suspension and Hairy Root Cultures — a Comparison

Abstract

Recently, the spectrum of secondary metabolites which might be produced in good levels by tissue culture techniques, has been extended by the use of organ cultures, especially of transformed root cultures. These hairy root cultures accumulate usually the spectrum of secondary metabolites in levels as found in roots of the intact plant. Nevertheless for technological purposes growth and product levels of many root cultures have to be optimized. Thus we wanted to analyze whether secondary pathways of root cultures would be affected by the same factors as known from studies with normal cultures. The ease of manipulating secondary pathways of suspension cultures has provided first insight into their regulatory controls. As activities of enzymes diverting primary metabolites into secondary pathways are often greatly induced under culture conditions favoring secondary metabolism, it has been suggested that these enzymes serve as one of diverse regulatory controls of secondary pathways. Therefore we were interested to see whether such enzymes undergo rapid changes in transformed root or suspension cultures. The availability of cell lines with different productivities let us compare the activities of such enzymes. Here we summarize some of our experiences in altering isoflavonoid levels of Lupinus and s-carbolines and serotonin of Peganum by variation of the medium composition.