Induction of Oxidative Stress and Antioxidative Mechanisms in Arabidopsis thaliana after Uranium Exposure at pH 7.5

Abstract

To evaluate the environmental impact of uranium (U) contamination, it is important to investigate the effects of U at ecologically relevant conditions. Since U speciation, and hence its toxicity, strongly depends on environmental pH, the present study aimed to investigate dose-dependent effects of U at pH 7.5. Arabidopsis thaliana plants (Mouse-ear Cress) were exposed for three days to different U concentrations at pH 7.5. In the roots, the increased capacities of ascorbate peroxidase and glutathione reductase indicate an important role for the ascorbate-glutathione cycle during U-induced stress. However, a significant decrease in the ascorbate redox state was observed after exposure to 75 and 100 µM U, indicating that those roots are severely stressed. In accordance with the roots, the ascorbate-glutathione cycle plays an important role in the antioxidative defence systems in A. thaliana leaves exposed to U at pH 7.5 as the ascorbate and glutathione biosynthesis were upregulated. In addition, small inductions of enzymes of the antioxidative defence system were observed at lower U concentrations to counteract the U-induced stress. However, at higher U concentrations it seems that the antioxidative defence system of the leaves collapses as reductions in enzyme activities and gene expression levels were observed.

Development of a metalloproteomic approach to analyse the response of Arabidopsis cells to uranium stress

“…[7][8][9][10][11] Uranium inhibits plant growth, modifies root growth and architecture, disrupts mineral nutrition and homeostasis, and affects photosynthesis. [12][13][14][15][16][17][18][19] At the cellular level, U induces nitric oxide and hydrogen peroxide production and triggers defence mechanisms against oxidative stress. 19,20 Also, U perturbs iron, phosphate and manganese homeostasis 9,14,21,22 and triggers important changes in the metabolome.…”

Dynamics of the membrane- and cell wall-associated proteome ofArabidopsis thalianaroots in response to uranium stress

“…iron, calcium, phosphorus, magnesium), and hormone synthesis and distribution ( i.e. auxin, jasmonic acid and salicylic acid) (Vanhoudt et al, 2010; Vanhoudt et al, 2011; Doustaly et al, 2014; Saenen et al, 2014; Saenen et al, 2015; Serre et al, 2019; Wu et al, 2022; Chen et al, 2022; Chen et al, 2023). In addition, U exposure leads to an overproduction of reactive oxygen species (ROS) (Gupta et al, 2020; Wu et al, 2022; Xiao et al, 2023).…”

Uncovering the physiological and cellular effects of uranium on the root system of Arabidopsis thaliana

“…Uranium interferes with plant nutrition, photosynthesis, and induces an oxidative stress (e.g. Vanhoudt et al, 2011aVanhoudt et al, ,b,c, 2014Aranjuelo et al, 2014;Saenen et al, 2014Saenen et al, , 2015Tewari et al, 2015). Also, it has been shown that U perturbs iron and phosphate homeostasis and may lead to phosphate starvation (Misson et al, 2009;Doustaly et al, 2014;Berthet et al, 2018).…”