PEROXIDASE PRODUCTION IN-VITRO BY ARMORACIA-LAPATHIFOLIA (HORSERADISH)-TRANSFORMED ROOT CULTURES - EFFECT OF ELICITATION ON LEVEL AND PROFILE OF ISOENZYMES

Transformed roots of Armoracia lapathifolia (horseradish) were establi shed by infection with Agrobacterium rhizogenes LBA 9402. They were us ed as a culture system in vitro for peroxidase production in vitro, to avoid many of the problems that affect the traditional production fro m field-grown species of Armoracia sp. The time course of growth of th ese cultures showed that total peroxidase attained maximum levels at t he end of the exponential growth phase. At this stage of culture, elic itation assays were performed with AgNO3 and CuSO4 as abiotic elicitor s and with fungal extracts of Verticillum sp., Monodyctis cataneae and Aspergillus niger as biotic elicitors. The best results were obtained with Verticillum sp., 24 h after elicitation, with an increase of app rox. 100% in peroxidase activity. The isoenzyme pattern analysed by is oelectric focusing revealed predominantly basic and acidic isoenzymes in both plant roots and transformed root cultures. Elicited samples sh owed a similar isoenzyme pattern with a slight increase in basic isoen zymes.