title: Role of nicotianamine in the intracellular delivery of metals and plant reproductive development.
abstract: Nicotianamine (NA), a chelator of metals, is ubiquitously present in higher plants. Nicotianamine aminotransferase (NAAT) catalyzes the amino group transfer of NA in the biosynthetic pathway of phytosiderophores and is essential for iron acquisition in graminaceous plants. The gene that encodes NAAT from barley was introduced into the nongraminaceous plant tobacco, which produces NA but not phytosiderophores. Transgenic tobacco plants (naat tobacco) that constitutively expressed the NAAT gene had young leaves with interveinal chlorosis and flowers that were abnormally shaped and sterile. Endogenous NA was consumed as a result of NAAT overproduction in naat tobacco. The resulting NA shortage caused disorders in internal metal transport, leading to these abnormal phenotypes. In addition to its role in long-distance metal transport, NA may be involved in the regulation of metal transfer within the cells. These results suggest that a shortage of NA impaired the functions of metal-requiring proteins, including transcription factors.
authors.affiliation: Laboratory of Plant Biotechnology, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Takahashi
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Terada
authors.forename: Izumi
authors.initials: I
authors.lastname: Nakai
authors.forename: Hiromi
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Etsuro
authors.initials: E
authors.lastname: Yoshimura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mori
authors.forename: Naoko K
authors.initials: NK
authors.lastname: Nishizawa
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D001383:Azetidinecarboxylic Acid / Q000031:analogs & derivatives* / Q000378:metabolism*; D001692:Biological Transport; D005298:Fertility; D035264:Flowers / Q000254:growth & development / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D001467:Hordeum / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D007504:Iron Radioisotopes; D008670:Metals / Q000378:metabolism*; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D000637:Transaminases / Q000235:genetics* / Q000378:metabolism; D015032:Zinc / Q000378:metabolism
chemical_list: D007504:Iron Radioisotopes; D008670:Metals; D010940:Plant Proteins; C082893:nicotianamine; D001383:Azetidinecarboxylic Acid; D007501:Iron; D019883:Alkyl and Aryl Transferases; C118230:nicotianamine synthase; D000637:Transaminases; C402173:nicotianamine aminotransferase, Hordeum vulgare; D015032:Zinc