title: Overexpression of rice glutaredoxins (OsGrxs) significantly reduces arsenite accumulation by maintaining glutathione pool and modulating aquaporins in yeast.
abstract: 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 (Δars) and Saccharomyces cerevisiae mutant strains (Δycf1, Δacr3). The expression of OsGrxs increased As tolerance in E. coli (Δars) mutant strain (up to 4 mM AsV and up to 0.6 mM AsIII). During AsIII exposure, S. cerevisiae (Δacr3) 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 (Δycf1) 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.
authors.affiliation: Genetics and Molecular Biology Division, CSIR-National Botanical Research Institute, India; Department of Biotechnology, Kumaun University, India.
authors.forename: Pankaj Kumar
authors.initials: PK
authors.lastname: Verma
authors.affiliation: Genetics and Molecular Biology Division, CSIR-National Botanical Research Institute, India; Department of Biotechnology, Kumaun University, India.
authors.forename: Shikha
authors.initials: S
authors.lastname: Verma
authors.affiliation: Environmental Material Division, CSIR-National Environmental Engineering Research Institute, India.
authors.forename: Alok Kumar
authors.initials: AK
authors.lastname: Meher
authors.affiliation: Department of Biotechnology, Kumaun University, India.
authors.forename: Veena
authors.initials: V
authors.lastname: Pande
authors.affiliation: Environmental Biotechnology Division, CSIR-National Botanical Research Institute, India.
authors.forename: Shekhar
authors.initials: S
authors.lastname: Mallick
authors.affiliation: Environmental Material Division, CSIR-National Environmental Engineering Research Institute, India.
authors.forename: Amit Kumar
authors.initials: AK
authors.lastname: Bansiwal
authors.affiliation: Environmental Biotechnology Division, CSIR-National Botanical Research Institute, India.
authors.forename: Rudra Deo
authors.initials: RD
authors.lastname: Tripathi
authors.affiliation: Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, USA.
authors.forename: Om Parkash
authors.initials: OP
authors.lastname: Dhankher
authors.affiliation: Genetics and Molecular Biology Division, CSIR-National Botanical Research Institute, India. Electronic address: chakrabartyd@nbri.res.in.
authors.forename: Debasis
authors.initials: D
authors.lastname: Chakrabarty
mesh_terms: D020346:Aquaporins / Q000378:metabolism*; D053502:Arsenate Reductases / Q000378:metabolism; D018053:Arsenites / Q000378:metabolism*; D001692:Biological Transport; D017343:Genes, Plant; D005816:Genetic Complementation Test; D054477:Glutaredoxins / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism*; D005980:Glutathione Reductase / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D011490:Protein Disulfide Reductase (Glutathione) / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D020346:Aquaporins; D018053:Arsenites; D054477:Glutaredoxins; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D053502:Arsenate Reductases; D005980:Glutathione Reductase; D011490:Protein Disulfide Reductase (Glutathione); D005978:Glutathione; C015001:arsenite
keywords: Arsenic; GSH; Glutaredoxin; Oryza sativa; OsGrxs