Differential response of antioxidant enzymes to cadmium stress in tolerant and sensitive cell line of cucumber (Cucumis sativus L.).

Abstract

Previously, a stable cell suspension of cucumber tolerant to 100 microM CdCl(2) was obtained (Gzyl & Gwóźdź, 2005, Plant Cell Tissue Organ Cult 80: 59-67). In this study, the relationship between the activity of antioxidant enzymes and cadmium tolerance of cucumber cells was analyzed. A cadmium-sensitive and the cadmium-tolerant cell lines were exposed to 100 microM and 200 microM CdCl(2) and the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APOX) and guaiacol peroxidase (POX) were determined. In the sensitive cell line, a decrease of total activity of SOD and POX was observed, whereas the activity of CAT and APOX significantly increased in metal-supplemented medium. By contrast, in the tolerant cells, the total activity of antioxidant enzymes decreased (SOD, CAT) or was maintained at approximately the same level (APOX, POX). Moreover, a different pattern of isoenzyme activity was observed in the tolerant and sensitive cells. These results suggest that an enhanced activity of antioxidant enzymes is not directly involved in the increased tolerance to cadmium of the selected cucumber cell line.

NADPH oxidase is involved in regulation of gene expression and ROS overproduction in soybean (Glycine max L.) seedlings exposed to cadmium

“…Accumulation of ROS in response to Cd, even after very short-term treatment, seems to be a common response observed in various plant species (reviewed in [5]). Although ROS overproduction might result from alterations in mitochondria and chloroplast functioning [6] and depletion of the antioxidant system [72], data in the literature indicate that in the case of short-term Cd stress, NADPH oxidase plays central role in ROS production. Stimulation of the NADPH oxidase activity by this metal has been observed in soybean, lupine, pea, cucumber, and rice plants [7][8][9][10]73].…”

The toxic Doppelganger: on the ionic and molecular mimicry of cadmium.

“…The reactive oxygen species generated in response to cadmium are also engaged in various signaling events (Chmielowska-Bąk & Deckert, 2012). The Cd-dependent over-production of ROS can result from disturbances in antioxidant systems, increased activity of NADPH oxidase, and alterations of mitochondria (Garnier et al, 2006;Romero-Puertas et al, 2007;Gzyl et al, 2009;Ognjanović et al, 2010;Chen et al, 2011;Chou et al, 2012). An important source of ROS are Fenton and Haber Weiss reactions catalyzed by redox-active metals, such as iron and copper (Kehrer, 2000).…”

A common response to common danger? Comparison of animal and plant signaling pathways involved in cadmium sensing

“…Another source of ROS are mitochondria alerted by Cd (Garnier et al 2006 ). Cadmium might also lead to a decrease in antioxidant enzyme activity and in this way contribute to an increase in ROS cellular levels (Cho and Seo 2005 ; Gzyl et al 2009 ; Ognjanović et al 2010 ; Romero-Puertas et al 2007 ). Reactive oxygen species interact with various cellular compounds and lead to their damage.…”