Production of hydrogen peroxide and hydroxyl radical in potato tuber during the necrotrophic phase of hemibiotrophic pathogen Phytophthora infestans infection

In this study, evidence is provided on the formation of hydrogen peroxide (H2O2) and hydroxyl radical (HO) in the potato tuber during the necrotrophic phase of the hemibiotrophic pathogen Phytophthora infestans infection. Using 3,3-diaminobenzidine tetrahydrochloride (DAB) imaging technique, the formation of H2O2 was demonstrated in P. infestans-infected potato tuber. For the first time, HO formation was demonstrated in P. infestans-infected potato tuber using electron paramagnetic resonance (EPR) spectroscopy. An enhancement in spontaneous ultra-weak photon emission indicated the extent of lipid peroxidation in the P. infestans-infected potato tuber. The data presented in this study reveal that the formation of H2O2 and HO in the P. infestans-infected potato tuber is associated with lipid peroxidation. It is proposed here that the ultra-weak photon emission can be used as a non-invasive indicator of the oxidative processes in the quality control at food industry.