Antioxidant response of Nicotiana tabacum cv. Bright Yellow 2 cells to cadmium and nickel stress

Abstract

Plant cell cultures are a suitable model system for investigation of the physiological mechanisms of tolerance to environmental stress. We have determined the effects of Cd (0.1 and 0.2 mM CdCl 2 ) and Ni (0.075 and 0.75 mM NiCl 2 ) on Nicotiana tabacum L. cv. Bright Yellow (TBY-2) cell suspension cultures over a 72-h period. Inhibition of growth, loss of cell viability and lipid peroxidation occurred, in general, only when the TBY-2 cells were grown at 0.2 mM CdCl 2 and at 0.75 mM NiCl 2 . At 0.1 mM CdCl 2 , a significant increase in growth was determined at the end of the experiment. Increases in the activities of all of the four enzymatic antioxidant defence systems tested, were induced by the two concentrations of Cd and Ni, but at different times during the period of metal exposure. Overall, the cellular antioxidant responses to Cd and Ni were similar and were apparently sufficient to avoid oxidative stress at the lower concentrations of Cd and Ni. The activities of glutathione reductase and glutathione S-transferase increased early but transiently, whereas the activities of catalase and guaiacol peroxidase increased in the latter half of the experimental period. Therefore it is likely that the metabolism of reduced glutathione was enhanced during the initial onset of the stress, while catalase and guaiacol-type peroxidase appeared to play a more important role in the antioxidant response once the stress became severe.

Toxicity symptoms of nickel in common bean

“…However, numerous evidences indicate that the Ni toxicity can be attributed also to oxidative stress at the cellular level (BACCOUCH et al, 2001;GONNELLI et al, 2001). Under stress conditions, including exposure to excessive concentrations of heavy metals, there is imbalance and removal of reactive oxygen species in plant tissues (GRATÃO et al, 2005;GRATÃO et al, 2008). This may consequently lead to oxidative damage of macromolecules such as lipids, proteins and nucleic acids (KEHRER, 2000).…”

Cadmium and zinc induced similar changes in protein and glycoprotein patterns in tobacco (nicotiana tabacum l.) seedlings and plants

“…This plant has been employed in studies on the production of useful recombinant proteins and antibodies, which have an application in medicine and industry (35). Moreover, tobacco has been found to be an extremely versatile system for all aspects of abiotic stress research, including the studies of physiological mechanisms, which lead to adverse environmental conditions (36,37).…”

Burkholderia sp. cadmium tolerance mechanism and its influence in phytoremediation

“…Heavy metals (HM), including Cd, generate oxidative stress in the cells and its toxicity is partially attributed to the metal capacity of inducing reactive oxygen species (ROS), damaging lipids, proteins and DNA (GRATÃO et al, 2005b;THORSEN et al, 2009). …”

“…that is found in aerobic and facultative anaerobic organisms, acting on the detoxification of superoxide radical Glutathione (GSH) is described as the compound responsible for the main cellular detoxification, including Cd inEscherichia coli (MASIP et al, 2006) (SCRUTTON et al, 1987), these reactive compounds oxidize glutathione, inactivating molecules. Glutathione reductase is the enzyme that reduces oxidized glutathione (GSSG) using NADPH (Figure 2.1) (GRATÃO et al, 2005b).…”

“…One important and well-described bioremediation strategy for reducing soil contaminants is phytoremediation, which uses plants that have the capability to take up HMs present in the soil, thereby allowing other, non-tolerant crops to be cultivated on the same soil after it has been remediated (YANG et al, 2005;SOUZA et al, 2013). Plant species that accumulate HMs have been effectively used to ameliorate HM contamination in soils, and a list of plant species that naturally hyper-accumulate Cd is available (GRATÃO et al, 2005b). Tomato plants in particular havebeen used as a model to study Cd phytoextraction and potential defence mechanisms in response to HMs GRATÃO et al, 2008a;MONTEIRO et al, 2011).…”