Distinct expression and function of three ammonium transporter genes (OsAMT1;1-1;3) in rice.
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:
Sonoda
Yutaka
Y
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Kita-ku N10-W8, Sapporo, 060-0810 Japan.
Ikeda
Akira
A
Saiki
Satomi
S
von Wirén
Nicolaus
N
Yamaya
Tomoyuki
T
Yamaguchi
Junji
J
D000595:Amino Acid Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D027682:Cation Transport Proteins; D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D009154:Mutation; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism* / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D002352:Carrier Proteins; D027682:Cation Transport Proteins; D010940:Plant Proteins; D020033:Protein Isoforms; D000644:Quaternary Ammonium Compounds; D012333:RNA, Messenger; C088952:ammonium transporters, plant