Sucrose metabolism and indoleglucosinolate production of immobilized horseradish cells

Abstract

The problem of transient primary or secondary metabolism remaining a persisting problem in plant cell cultures is discussed. Since secondary metabolites occurred mainly in differentiated tissues, an effort was made to mimic the cell-to-cell contact of multicellular organisms. Sucrose metabolism and indoleglucosinolate production from immobilized cells of Armoracia rusticanawere investigated. Immobilization acted by reducing the assimilation of the hexoses released into the culture medium. Although sucrose hydrolysis occurred prior to uptake, the decrease of acid invertase activity in immobilized cells was accompanied by an increased yield (2–3-fold) of the intracellular sucrose. Glucosinolates accumulated as indolic forms only during the stationary stage of cell growth. Their amount in immobilized cells may be increased 2-fold compared to the control cultures. On the other hand intracellular sucrose concentration declined whilst the cleavage activity of sucrose synthase increased simultaneously with production of indole-3-methyl- and 4-hydroxy-indole-3-methyl-glucosinolates. Thus, the role of cell immobilization in the biosynthesis of indoleglucosinolates is discussed.