Verma, Pankaj Kumar and Verma, Shikha and Meher, Alok Kumar and Pande, Veena and Mallick, Shekhar and Bansiwal, Amit and Tripathi, Rudra Deo and Dhankher, Om Parkash and Chakrabarty, Debasis (2016) Overexpression of rice glutaredoxins (OsGrxs) significantly reduces arsenite accumulation by maintaining glutathione pool and modulating aquaporins in yeast. Plant Physiology and Biochemistry, 106. pp. 208-217. ISSN 0981-9428

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Arsenic (As) is an acute poison and class I carcinogen, can cause a serious health risk. Staple crops like rice are the primary source of As contamination in human food. Rice grown on As contaminated areas accumulates higher As in their edible parts. Based on our previous transcriptome data, two rice glutaredoxins (OsGrx_C7 and OsGrx_C2.1) were identified that showed up-regulated expression during As stress. Here, we report OsGrx_C7 and OsGrx_C2.1 from rice involved in the regulation of intracellular arsenite (AsIII). To elucidate the mechanism of OsGrx mediated As tolerance, both OsGrxs were cloned and expressed in Escherichia coli (Dars) and Saccharomyces cerevisiae mutant strains (Dycf1, Dacr3). The expression of OsGrxs increased As tolerance in E. coli (Dars) mutant strain (up to 4 mM AsV and up to 0.6 mM AsIII). During AsIII exposure, S. cerevisiae (Dacr3) harboring OsGrx_C7 and OsGrx_C2.1 have lower intracellular AsIII accumulation (up to 30.43% and 24.90%, respectively), compared to vector control. Arsenic accumulation in As-sensitive S. cerevisiae mutant (Dycf1) also reduced significantly on exposure to inorganic As. The expression of OsGrxs in yeast maintained intracellular GSH pool and increased extracellular GSH concentration. Purified OsGrxs displays in vitro GSH-disulfide oxidoreductase, glutathione reductase and arsenate reductase activities. Also, both OsGrxs are involved in AsIII extrusion by altering the Fps1 transcripts in yeast and protect the cell by maintaining cellular GSH pool. Thus, our results strongly suggest that OsGrxs play a crucial role in the maintenance of the intracellular GSH pool and redox status of the cell during both AsV and AsIII stress and might be involved in regulating intracellular AsIII levels by modulation of aquaporin expression and functions.

Item Type: Article
Uncontrolled Keywords: Arsenic; GSH; OsGrxs; Glutaredoxin; Oryza Sativa
Subjects: Environmental Biotechnology
Depositing User: Dr. Amit Bansiwal
Date Deposited: 05 Apr 2017 12:00
Last Modified: 05 Apr 2017 12:00

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