title: Expression in Arabidopsis and cellular localization reveal involvement of rice NRAMP, OsNRAMP1, in arsenic transport and tolerance.
abstract: Irrigation of paddy fields to arsenic (As) containing groundwater leads to As accumulation in rice grains and causes serious health risk to the people worldwide. To reduce As intake via consumption of contaminated rice grain, identification of the mechanisms for As accumulation and detoxification in rice is a prerequisite. Herein, we report involvement of a member of rice NRAMP (Natural Resistance-Associated Macrophage Protein) transporter, OsNRAMP1, in As, in addition to cadmium (Cd), accumulation through expression in yeast and Arabidopsis. Expression of OsNRAMP1 in yeast mutant (fet3fet4) rescued iron (Fe) uptake and exhibited enhanced accumulation of As and Cd. Expression of OsNRAMP1 in Arabidopsis provided tolerance with enhanced As and Cd accumulation in root and shoot. Cellular localization revealed that OsNRAMP1 resides on plasma membrane of endodermis and pericycle cells and may assist in xylem loading for root to shoot mobilization. This is the first report demonstrating role of NRAMP in xylem mediated loading and enhanced accumulation of As and Cd in plants. We propose that genetic modification of OsNRAMP1 in rice might be helpful in developing rice with low As and Cd content in grain and minimize the risk of food chain contamination to these toxic metals.
authors.affiliation: CSIR-National Botanical Research Institute (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India.
authors.forename: Manish
authors.initials: M
authors.lastname: Tiwari
authors.forename: Deepika
authors.initials: D
authors.lastname: Sharma
authors.forename: Sanjay
authors.initials: S
authors.lastname: Dwivedi
authors.forename: Munna
authors.initials: M
authors.lastname: Singh
authors.forename: Rudra Deo
authors.initials: RD
authors.lastname: Tripathi
authors.forename: Prabodh Kumar
authors.initials: PK
authors.lastname: Trivedi
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D001151:Arsenic / Q000032:analysis / Q000378:metabolism*; D001692:Biological Transport; D018533:Biomass; D002104:Cadmium / Q000378:metabolism; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins; D009154:Mutation; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000502:physiology; D018520:Plant Shoots / Q000166:cytology / Q000235:genetics / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological; D015854:Up-Regulation; D052584:Xylem / Q000166:cytology / Q000235:genetics / Q000502:physiology; D000099173:Natural Resistance-associated Macrophage Protein 1
chemical_list: D001151:Arsenic; D002104:Cadmium; D027682:Cation Transport Proteins; D049452:Green Fluorescent Proteins; D010940:Plant Proteins; D000099173:Natural Resistance-associated Macrophage Protein 1
keywords: Cadmium; fet3fet4 yeast mutant; heavy metal; iron uptake; xylem loading