STIMULATION OF BERBERINE SECRETION AND GROWTH IN CELL-CULTURES OF THALICTRUM-MINUS

An endo-pectate lyase (PL; EC 4.2.2.2), originally cloned from the phytopathogenic bacterium Erwinia chrysanthemi EC16, was expressed in recA(-) E. coli strain DK1, purified to a single band by isoelectric focusing and used to induce berberine production in established plant suspension cultures of Thalictrum minus L. subsp. saxatile. Addition of 10(-9)M pectate lyase c (PLc) stimulated berberine production and enhanced secretion of the alkaloid into the medium. A lower concentration of PLc, 10(-11)M stimulated a transient two-fold increase in cell growth rate relative to untreated cultures. Parallel changes in L-phenylalanine ammonia lyase (PAL; EC 4.3. 1.5) activity with the rate of berberine synthesis and the inverse relationship between cell growth and berberine synthesis imply that berberine synthesis is stress-related in this cell line.