Effect of iron stress on Withania somnifera L.: antioxidant enzyme response and nutrient elemental uptake of in vitro grown plants

• Published in: Ecotoxicology (London) Vol. 24; no. 2; pp. 401 - 413
• Main Authors: Rout, Jyoti Ranjan, Behera, Sadhana, Keshari, Nitin, Ram, Shidharth Sankar, Bhar, Subhajit, Chakraborty, Anindita, Sudarshan, Mathummal, Sahoo, Santi Lata
• Format: Journal Article
• Language: English
• Published: Boston Springer-Verlag 01.03.2015; Springer US; Springer; Springer Nature B.V
• Subjects: Analysis; Antioxidants; Antioxidants - metabolism; Bioaccumulation; catalase; Catalase - genetics; Catalase - metabolism; DNA polymerases; Earth and Environmental Science; Ecology; Ecotoxicology; Electrophoresis, Polyacrylamide Gel; Environment; Environmental Management; Enzymatic activity; enzyme activity; Ethylenediaminetetraacetic acid; exposure duration; Gene expression; gene expression regulation; Gene Expression Regulation - drug effects; Genes; Germination; Iron; Iron - metabolism; Isoenzymes; isozymes; leaves; Nutrient balance; Nutrient concentrations; Nutrients; Oxidative stress; peroxidase; Peroxidase - genetics; Peroxidase - metabolism; Plant Proteins - genetics; Plant Proteins - metabolism; plant stress; Plant tissues; Plants (organisms); Plants, Medicinal - genetics; Plants, Medicinal - metabolism; polyacrylamide gel electrophoresis; Povidone; reverse transcriptase polymerase chain reaction; Sod; Stresses; Superoxide; superoxide dismutase; Superoxide Dismutase - genetics; Superoxide Dismutase - metabolism; tissues; Withania - genetics; Withania - metabolism; Withania somnifera; X-radiation; Iron stress; Gene expression; L; Bioaccumulation; Antioxidant enzymes; Proton induced X-ray emission (PIXE)
• ISSN: 0963-9292; 1573-3017
• DOI: 10.1007/s10646-014-1389-1

In the present study the response of antioxidant enzyme activities and the level of expression of their corresponding genes on bioaccumulation of iron (Fe) were investigated. In vitro germinated Withania somnifera L. were grown in Murashige and Skoog’s liquid medium with increasing concentrations (0, 25, 50, 100 and 200 µM) of FeSO₄for 7 and 14 days. Root and leaf tissues analyzed for catalase (CAT, EC 1.11.1.6), superoxide dismutase (SOD, EC 1.15.1.1) and guaiacol peroxidase (GPX, EC 1.11.1.7), have shown an increase in content with respect to exposure time. Isoforms of CAT, SOD and GPX were separated using non-denaturing polyacrylamide gel electrophoresis and observed that the isoenzymes were greatly affected by higher concentrations of Fe. Reverse transcriptase polymerase chain reaction analysis performed by taking three pairs of genes of CAT (RsCat, Catalase1, Cat1) and SOD (SodCp, TaSOD1.2, MnSOD) to find out the differential expression of antioxidant genes under Fe excess. RsCat from CAT and MnSOD from SOD have exhibited high levels of gene expression under Fe stress, which was consistent with the changes of the activity assayed in solution after 7 days of treatment. Analysis by proton induced X-ray emission exhibited an increasing uptake of Fe in plants by suppressing and expressing of other nutrient elements. The results of the present study suggest that higher concentration of Fe causes disturbance in nutrient balance and induces oxidative stress in plant.