title: Increased nicotianamine biosynthesis confers enhanced tolerance of high levels of metals, in particular nickel, to plants.
abstract: Nicotianamine, a plant-derived chelator of metals, is produced by the trimerization of S-adenosylmethionine catalyzed by nicotianamine synthase. We established transgenic Arabidopsis and tobacco plants that constitutively overexpress the barley nicotianamine synthase gene. Nicotianamine synthase overexpression resulted in increased biosynthesis of nicotianamine in transgenic plants, which conferred enhanced tolerance of high levels of metals, particularly nickel, to plants. Promoter activities of four nicotianamine synthase genes in Arabidopsis were all increased in response to excess nickel, suggesting that nicotianamine plays an important role in the detoxification of nickel in plants. Furthermore, transgenic tobacco plants with a high level of nicotianamine grew well in a nickel-enriched serpentine soil without developing any symptoms of nickel toxicity. Our results indicate that nicotianamine plays a critical role in metal detoxification, and this can be a powerful tool for use in phytoremediation.
authors.affiliation: Graduate School of Agricultural and Life Science, University of Tokyo, Bunkyo-ku, Japan.
authors.forename: Suyeon
authors.initials: S
authors.lastname: Kim
authors.forename: Michiko
authors.initials: M
authors.lastname: Takahashi
authors.forename: Kyoko
authors.initials: K
authors.lastname: Higuchi
authors.forename: Kyoko
authors.initials: K
authors.lastname: Tsunoda
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: D000222:Adaptation, Physiological; D019883:Alkyl and Aryl Transferases / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D001383:Azetidinecarboxylic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001483:Base Sequence; D015152:Blotting, Northern; D017931:DNA Primers; D017343:Genes, Plant; D008670:Metals / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D014026:Nicotiana / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology
chemical_list: D017931:DNA Primers; D008670:Metals; C082893:nicotianamine; D001383:Azetidinecarboxylic Acid; D019883:Alkyl and Aryl Transferases; C118230:nicotianamine synthase