Hairy Root Cultures of Peganum harmala II. Characterization of Cell Lines and Effect of Culture Conditions on the Accumulation of ß-Carboline Alkaloids and Serotonin

Abstract

Abstract Hairy root cultures of Peganum harmala established by genetic transformation with Agrobacterium rhizogenes wild type strains A4, 15834 or carrying the binary vector pLTCgus 1, respectively, were analyzed with respect to their tryptophan-derived metabolites. Beside the previously detected β-carboline alkaloids harmine, harmol, harmaline and harmalol all hairy root cultures were found to contain the β-carboline glucoside ruine and serotonin. The appearance of the root cultures and the levels of β-carboline alkaloids were greatly affected by the nitrogen source of the medium. In the presence of higher levels of ammonium ions (as in MS medium) the roots were short and thick, while in B50 medium (low ammonium) they were thin and long. Ammonium ions had a negative effect on the levels of β-carbolines. The best root cultures accumulated on B50 1.5-2% β-carbolines on a dry mass basis and in the presence of 6% sucrose ca. 10 mg β-carbolines/L x d were formed. In the presence of phytohorm ones root cultures were converted into low producing suspension cultures, from which the highly productive roots were reinduced on phytohormone-free medium.