title: The OsNRAMP1 iron transporter is involved in Cd accumulation in rice.
abstract: Cadmium (Cd) is a heavy metal toxic to humans and the accumulation of Cd in the rice grain is a major agricultural problem, particularly in Asia. The role of the iron transporter OsNRAMP1 in Cd uptake and transport in rice was investigated here. An OsNRAMP1:GFP fusion protein was localized to the plasma membrane in onion epidermal cells. The growth of yeast expressing OsNRAMP1 was impaired in the presence of Cd compared with yeast transformed with an empty vector. Moreover, the Cd content of OsNRAMP1-expressing yeast exceeded that of the vector control. The expression of OsNRAMP1 in the roots was higher in a high Cd-accumulating cultivar (Habataki) than a low Cd-accumulating cultivar (Sasanishiki) regardless of the presence of Cd, and the amino acid sequence of OsNRAMP1 showed 100% identity between Sasanishiki and Habataki. Over-expression of OsNRAMP1 in rice increased Cd accumulation in the leaves. These results suggest that OsNRAMP1 participates in cellular Cd uptake and Cd transport within plants, and the higher expression of OsNRAMP1 in the roots could lead to an increase in Cd accumulation in the shoots. Our results indicated that OsNRAMP1 is an important protein in high-level Cd accumulation in rice.
authors.affiliation: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Takahashi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ishimaru
authors.forename: Takeshi
authors.initials: T
authors.lastname: Senoura
authors.forename: Hugo
authors.initials: H
authors.lastname: Shimo
authors.forename: Satoru
authors.initials: S
authors.lastname: Ishikawa
authors.forename: Tomohito
authors.initials: T
authors.lastname: Arao
authors.forename: Hiromi
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Naoko K
authors.initials: NK
authors.lastname: Nishizawa
mesh_terms: D000595:Amino Acid Sequence; D001692:Biological Transport; D002104:Cadmium / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant; D007501:Iron / Q000378:metabolism; D012275:Oryza / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D027682:Cation Transport Proteins; D010940:Plant Proteins; D002104:Cadmium; D007501:Iron