Investigating the underlying mechanism of cadmium-induced plant adaptive response to genotoxic stress

• Published in: Ecotoxicology and environmental safety Vol. 209; p. 111817
• Main Authors: Chakrabarti, Manoswini, Mukherjee, Anita
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.02.2021; Elsevier
• Subjects: Cadmium - toxicity; Cadmium Chloride - toxicity; Cadmium-priming; Comet Assay; DNA damage; DNA Damage - physiology; DNA Methylation; DNA Repair; Ethyl Methanesulfonate - toxicity; Metabolic inhibitors; Methylation-sensitive comet assay; Mutagens - toxicity; Onions - drug effects; Onions - physiology; Oxidative Stress; Oxidative stress response; Plant Roots - drug effects; Soil Pollutants - toxicity; Vicia faba - drug effects; Vicia faba - physiology; DNA methylation; Cadmium-priming; Metabolic inhibitors; DNA damage; Oxidative stress response; Methylation-sensitive comet assay
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2020.111817

Plants as sessile organisms have developed some unique strategies to withstand environmental stress and adaptive response (AR) is one of them. In the present study Cadmium (Cd)-induced AR was evaluated to ameliorate the genotoxicity of a known chemical mutagen ethyl methanesulphonate (EMS) based on cytotoxicity, genotoxicity and oxidative stress in two model plant systems Allium cepa L. and Vicia faba L. Priming the plants with cadmium chloride (CdCl2, 25 and 50 μM) reduced the genotoxicity of EMS (0.25 mM). Cd-induced AR was evident by the magnitude of adaptive response (MAR) values calculated for cytotoxicity, genotoxicity and biochemical parameters. In addition the involvement of some major metabolic pathways and epigenetic modifications in AR was investigated. Metabolic blockers of protein kinase cascades, DNA repair, oxidative stress and de novo translation interfered with the adaptive response implying their role in AR whereas, inhibitors involved in post-replication repair and autophagy were ineffective implicating that they probably have no role in the AR studied. Moreover to find the role of DNA methylation in AR, methylation-sensitive comet assay was carried out. Simultaneously 5-methyl- 2'-deoxycytidine (5mdC) levels were quantified by HPLC (high performance liquid chromatography). AR was eliminated in cells treated with a demethylating agent, 5-aza- 2'deoxycytidine (AZA). Results implied a contribution of DNA hypermethylation. To the best of our knowledge this is a first report correlating DNA methylation to Cd-induced adaptive response in plants undergoing genotoxic stress. [Display omitted] •Cadmium (Cd)-conditioning confers protection to EMS-induced genotoxicity in Allium cepa L. and Vicia faba L.•Blockers of DNA repair, de novo translation, oxidative stress, protein kinase pathway inhibited Cd-induced adaptive response.•Metabolic inhibitors of autophagy and post-replication repair pathway did not affect Cd-induced adaptive response.•DNA methylation plays a positive role in Cd-induced plant adaptive response.