Modification of plasma membrane NADPH oxidase activity in cucumber seedling roots in response to cadmium stress

• Published in: Plant science (Limerick) 2015-05, Vol.234, p.50-59
• Main Authors: Jakubowska, Dagmara, Janicka-Russak, Małgorzata, Kabała, Katarzyna, Migocka, Magdalena, Reda, Małgorzata
• Format: Article
• Language: English
• Subjects: Base Sequence; Cadmium; Cadmium - toxicity; Cell Membrane - enzymology; Cucumis sativus - drug effects; Cucumis sativus - enzymology; Cucumis sativus - genetics; Malate Dehydrogenase - genetics; Malate Dehydrogenase - metabolism; Molecular Sequence Data; NADPH oxidase; NADPH Oxidases - genetics; NADPH Oxidases - metabolism; NADPH-generating enzymes; Phylogeny; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Roots - drug effects; Plant Roots - enzymology; Plant Roots - genetics; Plasma membrane; Proton-Translocating ATPases - genetics; Proton-Translocating ATPases - metabolism; Seedlings - drug effects; Seedlings - enzymology; Seedlings - genetics; Sequence Analysis, DNA
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/j.plantsci.2015.02.005

•Cadmium stimulates the activity of NADPH oxidase in cucumber seedling roots.•The activity of NADPH dehydrogenases is increased under cadmium stress.•Nine genes encoding NADPH oxidase in cucumber roots were identified.•Transcript levels of NADPH oxidase genes increased in roots treated with cadmium. The aim of this study was to investigate the effect of cadmium on plasma membrane (PM) NADPH oxidase activity in cucumber roots. Plants were treated with cadmium for 1, 3 or 6 days. Some of the plants after 3-day exposure to cadmium were transferred to a medium without the heavy metal for the next 3 days. Treatment of plants with cadmium for 6 days stimulated the activity of NADPH oxidase. The highest stimulation of O2•− production by NADPH oxidase was observed in post-stressed plants, which was correlated with the stimulation of activity of PM H+-ATPase in the same conditions. In order to examine the effects of cadmium stresses on the expression level of genes encoding NADPH oxidase, putative cucumber homologs encoding RBOH proteins were selected and a real-time PCR assay was performed. NADPH is a substrate for oxidase; thus alterations in the activity of glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, NADP-isocitrate dehydrogenase and NADP-malic enzyme under cadmium stress were studied. The activity of NADPH dehydrogenases was increased under cadmium stress. The results indicate that PM NADPH oxidase could be involved in plants’ response to cadmium stress by affecting the activity of PM H+-ATPase, and NADPH-generating enzymes could play important roles in this process.