MEMBRANE, CYTOSOLIC, AND NUCLEAR RESPONSES INDUCED BY OLIGOGALACTURONIDES IN SUSPENSION-CULTURED CARROT CELLS

Oligogalacturonides were applied at a concentration of 0.2 mg m(-1) to Daucus carota cells and protoplasts. Fractions containing oligomers o f degree of polymerisation greater than or equal to 9 in the presence of 150 mM NaCl and 0.5 mM CaCl2 (''high calcium'' conditions) triggere d a cytosolic calcium mobilisation, membrane depolarisation and cytoso lic acidification. These membrane and cytosolic events coincided with the accumulation of transcripts encoding phenylalanine ammonialyase an d catalytic activation of the enzyme. The effect of signal transductio n modulators were investigated on oligogalacturonide-induced phenylala nine ammonia-lyase enzyme and gene activation in suspension-cultured c arrot cells.