Differential gene expression for isozymes in somatic mutants of Vitis vinifera L. (Vitaceae)

Isozyme electrophoresis was used as a method to provide a measure of relationship among Italia, Rubi, Benitaka, and Brasil cv of Vitis vinifera traditionally grown in Marialva, a town in the northwestern region of the state of Paraná, southern Brazil. No allelic variation was observed for esterase (EST), malate dehydrogenase (MDH), peroxidase (POD), glutamate dehydrogenase (GTDH), alkaline phosphatase (AKP), acid phosphatase (ACP), and aspartate amino transferase (AAT). Tissue specific and variation in staining intensity of EST, MDH, POD, and GTDH isozymes indicate differential gene expression in colour grape varieties. Regulatory genes may be operative in determining the number of molecules of enzymes in a cell and determining the berry skin polymorphism in four cultivars. Change frequency for berry skin colour suggest the occurrence of somatic crossing-over in naturally cultivated plants and a periclinal chimerism in Brasil cv. The four grape colour cultivars seem to be clones of the same cultivar.