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Zinc-Dependent Protection of Tobacco and Rice Cells From Aluminum-Induced Superoxide-Mediated Cytotoxicity.

Lin C, Hara A, Comparini D, Bouteau F, Kawano T - Front Plant Sci (2015)

Bottom Line: Earlier studies suggested that lack of zinc often results in ROS-mediated oxidative damage to plant cells.In the present study, the effect of Zn(2+) on Al(3+)-induced superoxide generation in the cell suspension cultures of tobacco (Nicotiana tabacum L., cell-line, BY-2) and rice (Oryza sativa L., cv.Obtained results indicated that presence of Zn(2+) at physiological concentrations can protect the cells by preventing the Al(3+)-induced superoxide generation and cell death.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Environmental Engineering and Graduate School of Environmental Engineering, The University of Kitakyushu , Kitakyushu, Japan.

ABSTRACT
Al(3+) toxicity in growing plants is considered as one of the major factors limiting the production of crops on acidic soils worldwide. In the last 15 years, it has been proposed that Al(3+) toxicity are mediated with distortion of the cellular signaling mechanisms such as calcium signaling pathways, and production of cytotoxic reactive oxygen species (ROS) causing oxidative damages. On the other hand, zinc is normally present in plants at high concentrations and its deficiency is one of the most widespread micronutrient deficiencies in plants. Earlier studies suggested that lack of zinc often results in ROS-mediated oxidative damage to plant cells. Previously, inhibitory action of Zn(2+) against lanthanide-induced superoxide generation in tobacco cells have been reported, suggesting that Zn(2+) interferes with the cation-induced ROS production via stimulation of NADPH oxidase. In the present study, the effect of Zn(2+) on Al(3+)-induced superoxide generation in the cell suspension cultures of tobacco (Nicotiana tabacum L., cell-line, BY-2) and rice (Oryza sativa L., cv. Nipponbare), was examined. The Zn(2+)-dependent inhibition of the Al(3+)-induced oxidative burst was observed in both model cells selected from the monocots and dicots (rice and tobacco), suggesting that this phenomenon (Al(3+)/Zn(2+) interaction) can be preserved in higher plants. Subsequently induced cell death in tobacco cells was analyzed by lethal cell staining with Evans blue. Obtained results indicated that presence of Zn(2+) at physiological concentrations can protect the cells by preventing the Al(3+)-induced superoxide generation and cell death. Furthermore, the regulation of the Ca(2+) signaling, i.e., change in the cytosolic Ca(2+) ion concentration, and the cross-talks among the elements which participate in the pathway were further explored.

No MeSH data available.


Related in: MedlinePlus

Competitive inhibition of the Al3+-induced O2•– generation by Zn2+ in tobacco cell suspension culture. (A) Effect of Zn2+ on Al3+-induced O2•– generation. (B)In vivo Lineweaver–Burk plot analysis.
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Figure 5: Competitive inhibition of the Al3+-induced O2•– generation by Zn2+ in tobacco cell suspension culture. (A) Effect of Zn2+ on Al3+-induced O2•– generation. (B)In vivo Lineweaver–Burk plot analysis.

Mentions: Application of double-reciprocal plot analysis for studying the behavior of living plants or cells, so-called in vivo Lineweaver–Burk plot analysis was carried out to assess the mode of Al3+/Zn2+ interaction according to the procedure described elsewhere (Kawano et al., 2003b). By making use of linear dose-dependency in the limited range of Al3+ concentrations (up to 3 mM) in 4 DAI culture of tobacco BY-2 cell, the in vivo kinetic analysis was carried out by assuming Al3+ as a ligand to the putative Al3+ receptors on the cells and Zn2+ as an inhibitor (Figure 5A). The reciprocals of the CLA-CL yields (1/CLA-CL) were plotted against the reciprocals of Al3+ concentrations (1/[Al3+]). Linear relationship between 1/CLA-CL and 1/[Al3+] were obtained both in the presence and absence of Zn2+ (Figure 5B). In the presence of Zn2+, the apparent Km for Al3+ was elevated from 113 μM (control) to 376 μM (0.1 mM Zn2+; ca. 3.3-fold increase), while Vmax for Al3+-induced CLA-CL was not drastically altered. Vmax for Al3+-induced response in the absence of Zn2+ was calculated to be 14.3 rcu. In the presence of 0.1 mM Zn2+, Vmax was 18.6 rcu (ca. 30% increase). Therefore, the mode of Zn2+ action against Al3+ can be considered as a typical competitive inhibition.


Zinc-Dependent Protection of Tobacco and Rice Cells From Aluminum-Induced Superoxide-Mediated Cytotoxicity.

Lin C, Hara A, Comparini D, Bouteau F, Kawano T - Front Plant Sci (2015)

Competitive inhibition of the Al3+-induced O2•– generation by Zn2+ in tobacco cell suspension culture. (A) Effect of Zn2+ on Al3+-induced O2•– generation. (B)In vivo Lineweaver–Burk plot analysis.
© Copyright Policy
Related In: Results  -  Collection

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Figure 5: Competitive inhibition of the Al3+-induced O2•– generation by Zn2+ in tobacco cell suspension culture. (A) Effect of Zn2+ on Al3+-induced O2•– generation. (B)In vivo Lineweaver–Burk plot analysis.
Mentions: Application of double-reciprocal plot analysis for studying the behavior of living plants or cells, so-called in vivo Lineweaver–Burk plot analysis was carried out to assess the mode of Al3+/Zn2+ interaction according to the procedure described elsewhere (Kawano et al., 2003b). By making use of linear dose-dependency in the limited range of Al3+ concentrations (up to 3 mM) in 4 DAI culture of tobacco BY-2 cell, the in vivo kinetic analysis was carried out by assuming Al3+ as a ligand to the putative Al3+ receptors on the cells and Zn2+ as an inhibitor (Figure 5A). The reciprocals of the CLA-CL yields (1/CLA-CL) were plotted against the reciprocals of Al3+ concentrations (1/[Al3+]). Linear relationship between 1/CLA-CL and 1/[Al3+] were obtained both in the presence and absence of Zn2+ (Figure 5B). In the presence of Zn2+, the apparent Km for Al3+ was elevated from 113 μM (control) to 376 μM (0.1 mM Zn2+; ca. 3.3-fold increase), while Vmax for Al3+-induced CLA-CL was not drastically altered. Vmax for Al3+-induced response in the absence of Zn2+ was calculated to be 14.3 rcu. In the presence of 0.1 mM Zn2+, Vmax was 18.6 rcu (ca. 30% increase). Therefore, the mode of Zn2+ action against Al3+ can be considered as a typical competitive inhibition.

Bottom Line: Earlier studies suggested that lack of zinc often results in ROS-mediated oxidative damage to plant cells.In the present study, the effect of Zn(2+) on Al(3+)-induced superoxide generation in the cell suspension cultures of tobacco (Nicotiana tabacum L., cell-line, BY-2) and rice (Oryza sativa L., cv.Obtained results indicated that presence of Zn(2+) at physiological concentrations can protect the cells by preventing the Al(3+)-induced superoxide generation and cell death.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Environmental Engineering and Graduate School of Environmental Engineering, The University of Kitakyushu , Kitakyushu, Japan.

ABSTRACT
Al(3+) toxicity in growing plants is considered as one of the major factors limiting the production of crops on acidic soils worldwide. In the last 15 years, it has been proposed that Al(3+) toxicity are mediated with distortion of the cellular signaling mechanisms such as calcium signaling pathways, and production of cytotoxic reactive oxygen species (ROS) causing oxidative damages. On the other hand, zinc is normally present in plants at high concentrations and its deficiency is one of the most widespread micronutrient deficiencies in plants. Earlier studies suggested that lack of zinc often results in ROS-mediated oxidative damage to plant cells. Previously, inhibitory action of Zn(2+) against lanthanide-induced superoxide generation in tobacco cells have been reported, suggesting that Zn(2+) interferes with the cation-induced ROS production via stimulation of NADPH oxidase. In the present study, the effect of Zn(2+) on Al(3+)-induced superoxide generation in the cell suspension cultures of tobacco (Nicotiana tabacum L., cell-line, BY-2) and rice (Oryza sativa L., cv. Nipponbare), was examined. The Zn(2+)-dependent inhibition of the Al(3+)-induced oxidative burst was observed in both model cells selected from the monocots and dicots (rice and tobacco), suggesting that this phenomenon (Al(3+)/Zn(2+) interaction) can be preserved in higher plants. Subsequently induced cell death in tobacco cells was analyzed by lethal cell staining with Evans blue. Obtained results indicated that presence of Zn(2+) at physiological concentrations can protect the cells by preventing the Al(3+)-induced superoxide generation and cell death. Furthermore, the regulation of the Ca(2+) signaling, i.e., change in the cytosolic Ca(2+) ion concentration, and the cross-talks among the elements which participate in the pathway were further explored.

No MeSH data available.


Related in: MedlinePlus