Subcellular compartment of shikimic acid and phenylalanine in buckwheat cell suspension cultures grown in the presence of shikimate pathway inhibitors

Cell suspension cultures of buckwheat (Fagopyrum esculentum Moench) accumulate up to 8 μmol/g fresh wt. shikimic acid, when grown in the presence of 0.5 mM glyphosate, an inhibitor of 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase and up to 6 μmol/g fresh wt. phenylalanine, when grown in the presence of 0.5 mM L-α-aminooxy-β-phenylpropionic acid (AOPP), an inhibitor of phenylalanine ammonia-lyase. Based on α-mannosidase activity as a vacuolar marker enzyme the accumulated metabolites in inhibitor-treated cells were found to be contained nearly exclusively in the vacuolar compartment. Protoplasts, as well as isolated vacuoles, were able to take up shikimate-3-phosphate and hydrolyze the phosphate ester.