Role of nicotianamine in the intracellular delivery of metals and plant reproductive development.
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.
Takahashi
Michiko
M
Laboratory of Plant Biotechnology, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Terada
Yasuko
Y
Nakai
Izumi
I
Nakanishi
Hiromi
H
Yoshimura
Etsuro
E
Mori
Satoshi
S
Nishizawa
Naoko K
NK
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
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