Physiological responses of ‘Italia’ grapevines infected with Esca pathogens

Physiological features were examined of a 20-year-old Vitis vinifera ‘Italia’ table grape vineyard cropped in Apulia, Italy. Healthy vines with no foliar symptoms and any indications wood or berry alterations, natural infections by Phaeoacremonium minimum (syn. P. aleophilum) Phaeomoniella chlamydospora showing brown streaking symptoms, naturally infected minimum, Fomitiporia mediterranea white rot surveyed. Bleeding xylem sap, collected at bud-break from healthy showed the greatest total ascorbic acid level, while had viscosity coefficient, glutathione concentration, plant growth regulator activities. Compared to vines, leaves affected sampled during unfolded leaf, fruit setting, cluster closing bunch ripening vine stages, reduced fresh dry weights, chlorophyll concentrations, increased leaf surface area. Low weak redox state, moderate levels dehydroascorbic oxidized also detected these vines. Analyses activities dehydroascorbate reductase, ascorbate free radical reductase diseased The cell membrane damage, associated lipid peroxidation, was coupled high hydrogen peroxide concentrations. These changes could contribute death symptom development. ascorbate-glutathione cycle supports grapevine susceptibility Esca complex-associated fungi.