ROLE OF SALICYLIC-ACID AND INTRACELLULAR CA2-CULTURE( IN THE INDUCTION OF CHITINASE ACTIVITY IN CARROT SUSPENSION)

Treatment of carrot suspension culture with a fungal cell wall prepara tion induced the production of chitinase. This treatment also caused a n accumulation of salicylic acid both in the cells and in the extracel lular medium. Culture medium of induced cells, which contained elevate d levels of salicylic acid, was able to induce chitinase activity in a non-induced suspension culture. Exogenous supply of authentic salicyl ic acid induced chitinase activity in carrot cells more rapidly than t he fungal cell wall. Removal of extracellular Ca2+ by treatment with t he calcium chelator, EGTA [ethylene glycol bis(beta-aminoethyl ether)N ,N'-tetraacetic acid], abolished the elicitor-mediated production of b oth salicylic acid and chitinase. Verapamil caused similar effects, wh ereas the addition of the Ca2+ ionophore A23187, enhanced these cellul ar responses in the absence of elicitor. These observations suggest th at Ca2+ plays an important role in the induced production of chitinase and salicylic acid.