Antioxidant enzymes as biochemical markers for sharka resistance in apricot

The activity of antioxidant enzymes in different apricot (Prunus armeniaca L.) cultivars, resistant or susceptible to Plum pox virus (PPV), was analyzed during the years 2002 and 2003. Resistant cultivars showed higher activities of catalase (CAT), ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) than susceptible cultivars. Only CuZn-SOD isozymes were detected in the apricot cultivars. However, no correlation was observed between this isozyme pattern and the resistance to PPV. On the other hand, PPV-resistant apricot cultivars could have a greater capability for elimination of H₂O₂ and recycling of ascorbate-glutathione cycle, and they have at least two of these enzymatic activities (CAT, APX and DHAR) over the average. In contrast, this response was not observed in the susceptible cultivars. All these data suggest that the activities of CAT, APX and DHAR could be used as biochemical markers of sharka resistance in apricot.