Distinct expression and function of three ammonium transporter genes (OsAMT1;1-1;3) in rice [Oryza sativa]

• Published in: Plant and cell physiology Vol. 44; no. 7; pp. 726 - 734
• Main Authors: Sonoda, Y. (Hokkaido Univ., Sapporo (Japan)), Ikeda, A, Saiki, S, von Wiren, N.v, Yamaya, T, Yamaguchi, J
• Format: Journal Article
• Language: English
• Published: Japan Oxford University Press 01.07.2003; Oxford Publishing Limited (England)
• Subjects: Amino Acid Sequence; AMMONIUM; ammonium transporter; AMT; Blotting, Northern; Blotting, Southern; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cation Transport Proteins; Cloning, Molecular; GENE EXPRESSION; Gene Expression Regulation, Plant - drug effects; In Situ Hybridization; Keywords: Ammonium uptake — Ammonium regulation — AMT1 — In situ hybridization — Oryza sativa — Yeast complementation; Molecular Sequence Data; Mutation; NUTRIENT TRANSPORT; NUTRIENT UPTAKE; Oryza - genetics; Oryza - metabolism; ORYZA SATIVA; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Roots - genetics; Plant Roots - metabolism; Protein Isoforms - genetics; Protein Isoforms - metabolism; Quaternary Ammonium Compounds - metabolism; Quaternary Ammonium Compounds - pharmacology; reverse transcription-PCR; RNA, Messenger - genetics; RNA, Messenger - metabolism; RT-PCR; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Sequence Homology, Amino Acid
• ISSN: 0032-0781; 1471-9053
• DOI: 10.1093/pcp/pcg083

To study the regulation of ammonium uptake into rice roots, three ammonium transporter genes (OsAMT1;1, 1;2 and 1;3; Oryza sativa ammonium transporter) were isolated and examined. OsAMT1s belong to AMT1 family, containing 11 putative transmembrane-spanning domains. Southern blot analysis and screening of the rice genome database confirmed that with OsAMT1;1-1;3 the complete AMT1 family of rice had been isolated. Heterologous expression of OsAMT1s in the yeast Saccharomyces cerevisiae mutant 31019b showed that all three OsAMT1s exhibit ammonium transport activity. Northern blot analysis showed a distinct expression pattern for the three genes; more constitutive expression in shoots and roots for OsAMT1;1, root-specific and ammonium-inducible expression for OsAMT1;2, and root-specific and nitrogen-derepressible expression for OsAMT1;3. In situ mRNA detection revealed that OsAMT1; 2 is expressed in the central cylinder and cell surface of root tips. This gene expression analysis revealed a distinct nitrogen-dependent regulation for AMTs in rice, differing from that in tomato or Arabidopsis.