Plum pox virus (PPV) infection produces an imbalance on the antioxidative systems in Prunus species

Hernández, J. A. and Díaz-Vivancos, P. and Rubio, M. and Olmos, E. and Clemente, M. J. and Ros-Barceló, A. and Martínez-Gómez, P. (2007) Plum pox virus (PPV) infection produces an imbalance on the antioxidative systems in Prunus species. Acta Phytopathologica et Entomologica Hungarica, 42 (2). pp. 209-221. ISSN 0238-1249

Text aphyt.42.2007.2.4.pdf Restricted to Repository staff only until 31 December 2027. Download (255kB)

Abstract

The effect of Plum pox virus (PPV) infection on the response of some antioxidant enzymes was studied in Prunus species showing different susceptibility to PPV. PPV infection produced changes in the antioxidant systems from the Prunus species at subcellular level. In general, in PPV susceptible plants, the infection produced a decrease in some antioxidant enzymes, mainly in chloroplasts. However, in peach cv GF305 (PPV-susceptible) also an increase in class I APX in the three compartments studied as well as an increase in POX took place. In contrast, the PPV-resistant plants showed a general increase of antioxidant enzymes in soluble, chloroplast and apoplastic fractions. Long-term PPV infection produced an oxidative stress only in susceptible plants, as observed by the increase in leaf lipid peroxidation, protein oxidation and electrolyte leakage as well as in apoplastic H2O2. This H2O2 increase was much higher in the PPV-susceptible than in the PPV-resistant plants. In peach, the increase in apoplastic H2O2 correlated with the rise in NADH-POX and PPO activities. However, in apricot leaves, no increases in apoplastic NADH-POX were observed, and the increases in apoplastic H2O2 correlated with increase in PPO activity in both cv. Real Fino (100%) and cv. SEO (40%), where a rise in SOD was detected, too. The specific inhibitor of NADPH oxidase, diphenylene iodonium (DPI), had only small effects on NADH oxidation, whereas it was inhibited almost completely by 1 mM KCN. Therefore, most of the NADH oxidation in the apoplastic space of Prunus species is due to NADH-POX and not NAD(P)H oxidase. In previous studies and by means of 2D electrophoresis, we showed that PPV infection produced the induction of a thaumatin-like protein as well as the decrease of mandelonitrile lyase (MDL) in peach apoplast. Mandelonitrile lyase catalyses the breakdown of mandelonitrile into benzaldehyde and cyanide. Benzaldehyde can be oxidised easily in vivo to produce benzoic acid, the precursor of salicylic acid. It was suggested that decreased MDL activity may result in a decreased SA biosynthesis in PPV-infected peach plants. It is also possible that a decline in antioxidant enzymes and an increase in ROS could be necessary for the establishment of infection and the replication and spread of some plant viruses, in agreement with results described by other authors. Results suggest that the higher antioxidant capacity showed by resistant SEO plants in comparison to PPV-susceptible plants could be associated, among other factors with their resistance to PPV.

Actions (login required)

Edit Item