Compartment-specific investigations of antioxidants and hydrogen peroxide in leaves of Arabidopsis thaliana during dark-induced senescence

Abstract

The aim of this study was to gain insight into the compartment-specific roles of ascorbate and glutathione in leaf senescence in Arabidopsis thaliana. The subcellular distribution of ascorbate, glutathione, and hydrogen peroxide (H2O2) was analyzed by transmission electron microscopy and correlated with the activity of antioxidative enzymes in wildtype plants and the ascorbate- and glutathione-deficient mutants vtc2-1 and pad2-1, respectively. Both mutants showed earlier and stronger senescence than the wildtype indicating the importance of a functioning ascorbate and glutathione cycle in the induction and regulation of senescence. Glutathione levels dropped drastically and up to 93 % in all cell compartments of wildtype plants and the vtc2-1 mutant within the first day of dark-induced senescence while ascorbate contents remained unchanged until the very end. Glutathione contents in mitochondria of pad2-1 mutants decreased more slowly over the first 7 days than compared to the other plants indicating an important role of glutathione in mitochondria in this mutant during senescence. The strongest decrease (84 %) of glutathione contents in wildtype plants at this time point was found in mitochondria indicating an important role of mitochondria for the induction of senescence and cell death events. Due to the general decrease of the antioxidative capacity, a strong accumulation of H2O2 was observed in cell walls, plastids, and the cytosol in all plants. Activities of glutathione reductase, dehydroascorbate reductase and catalase were strongly reduced while ascorbate peroxidase and monodehydroascorbate reductase were increased. The initial rapid drop of glutathione levels seemed to be the trigger for senescence, while ascorbate appeared to be the key factor in regulating senescence through controlling H2O2 levels by the oxidation of reduced ascorbate to monodehydroascorbate and the subsequent reduction to ascorbate by monodehydroascorbate reductase.Electronic supplementary materialThe online version of this article (doi:10.1007/s11738-016-2150-6) contains supplementary material, which is available to authorized users.

Formate dehydrogenase takes part in molybdenum and iron homeostasis and affects dark-induced senescence in plants

“…and Kräutler 2011; Liebsch and Keech 2016;Luschin-Ebengreuth and Zechmann 2016;Woo et al 2018). In particular, the Fe storage ferritin (Briat et al 2010;Ramirez et al 2011) takes part in both natural and dark-induced senescing programs (Tarantino et al 2003;Murgia et al 2007).…”

Plant Cell Wall Dynamics in Compatible and Incompatible Potato Response to Infection Caused by Potato Virus Y (PVYNTN)

“…Labeling quantification of cell wall associated proteins PR-2, CesA4 and extensin was based on the method proposed by Luschin-Ebengreuth and Zechmann [ 78 ], with modifications of the type of statistical method and program used for statistical analyses. Data on gold particle concentration was investigated by analysis of variance (ANOVA) and the post-hoc Tukey HSD test in STATISTICA software (StataSoft and TIBCO Software Inc., Palo Alto, CA, USA, version 13.0).…”

The Expression of Potato Expansin A3 (StEXPA3) and Extensin4 (StEXT4) Genes with Distribution of StEXPAs and HRGPs-Extensin Changes as an Effect of Cell Wall Rebuilding in Two Types of PVYNTN–Solanum tuberosum Interactions

“…A sample's time-point from mock or virus inoculation for TEM observation was selected based on qPCR results and immunofluorescent localization. After examination, labeling quantification of cell wall-associated proteins was based on the method proposed by Luschin-Ebengreuth and Zechmann [44], with modifications regarding the type of statistical method and program used for statistical analyses. Data for the gold particle concentrations were investigated by analysis of variance (ANOVA) and the post-hoc Tukey HSD test in STATISTICA software (StataSoft and TIBCO Software Inc., Palo Alto, CA, USA, version 13.0).…”