PEROXIDASE ISOENZYME PATTERNS IN CELL-CULTURES DERIVED FROM COTYLEDON, STEM, LEAF AND FRUIT FROM GRAPEVINE (VITIS-VINIFERA CV MONASTRELL)

The expression of peroxidase isoenzymes capable of oxidizing 4-hydroxy stilbenes was studied during the establishment of cell cultures derive d from different tissues (cotyledon, stem, leaf and fruit) of Vitis vi nifera cv. Monastrell vines. This was carried out in order to elucidat e whether different tissues of the same plant maintain persistent tiss ue-specific patterns of gene expression during in vitro culture or whe ther in vitro cultures are characterized by identical patterns of gene expression irrespective of the tissue's origin. The results illustrat ed that both the isozyme patterns and the substrate specificity of the peroxidase activity secreted to the medium are analogous for the prof ile of acidic (Prx A) and basic (Prx B) peroxidase isoenzymes, only qu antitative differences being shown in the neutral peroxidase : isoenzy me (Prx N) pattern. These results suggest that in vitro cultures of gr apevines are characterized by similar patterns of gene expression, ho matter what their tissue of origin.