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Effects of calcium and EGTA on thiol homeostasis and defense-related enzymes in Cd-exposed chickpea roots

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Abstract

Exposure of chickpea seeds (Cicer arietinum L.) to cadmium stress for 6 days resulted in growth reduction and oxidative stress installation as exemplified by a strong accumulation of H2O2 and a disruption of enzymatic and non-enzymatic defense systems. The enrichment of the seed germinating medium with calcium and ethylene glycol tetraacetic acid (EGTA) relieved the detrimental effect of Cd on root growth. This protective effect would be the result of (1) protein thiol protection, as evidenced by thioredoxin system activation, and of (2) the glutathione disulfide content decrease. The absence of corrective effect of effectors on glutathione redox state should be associated with the concomitant decrease in regeneration and consumption processes of reduced forms of glutathione, namely by glutathione reductase and glutathione peroxidase activities, respectively. Calcium and EGTA application led to oxidative stress alleviation as evidenced by H2O2 content decrease and the restoration of catalase and ascorbate peroxidase activities at a level similar to control roots. Moreover, the analysis of the transcriptional system relating to the up-cited enzymes revealed a decreased gene expression subsequent to the enrichment of germination medium with the effectors. The present research provided deeper insights into the mechanisms induced by Ca and EGTA to protect plant cell against Cd-induced oxidative injury.

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Acknowledgements

The present work was financially supported by the Tunisian Ministry of Higher Education and Scientific Research and by Graduate School of Environmental and Life Science, Okayama University (Japan). The authors wish to thank Mrs. Sihem Ben Hassine for technical assistance in HPLC analyses.

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Authors and Affiliations

  1. Plant Toxicology and Molecular Biology of Microorganisms, Faculty of Science of Bizerta, University of Carthage, 7021, Zarzouna, Tunisia

    Lamia Sakouhi, Sondès Rahoui, Ezzeddine El Ferjani & Abdelilah Chaoui

  2. Laboratory of Molecular Genetics, Immunology and Biotechnology, Faculty of Sciences of Tunis, University of Tunis El Manar, 2092, Tunis, Tunisia

    Charfeddine Gharsallah

  3. Graduate School of Environmental and Life Science, Okayama University, Okayama, 700-8530, Japan

    Shintaro Munemasa & Yoshiyuki Murata

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  1. Lamia Sakouhi
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Sakouhi, L., Rahoui, S., Gharsallah, C. et al. Effects of calcium and EGTA on thiol homeostasis and defense-related enzymes in Cd-exposed chickpea roots. Acta Physiol Plant 40, 20 (2018). https://doi.org/10.1007/s11738-017-2596-1

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