Regulation of a putative high-affinity nitrate transporter (Nrt2;1At) in roots of Arabidopsis thaliana.
Putative high-affinity nitrate (NO3-) transporter genes, designated Nrt2;1At and Nrt2;2At, were isolated from Arabidopsis thaliana by RT-PCR using degenerate primers. The genes shared 86% and 89% identity at the amino acid and nucleotide levels, respectively, while their proteins shared 30-73% identities with other eukaryotic high-affinity NO3- transporters. Both genes were induced by NO3-, but Nrt2;1At gene expression was not apparent in 2- and 5-day-old plants. By 10 days, and thereafter, Nrt2;1At gene expression in roots was substantially higher than for the Nrt2;2At gene. Root Nrt2;1At expression levels were strongly correlated with inducible high-affinity 13NO3- influx into intact roots under several treatment conditions. The use of inhibitors of N assimilation indicated that downregulation of Nrt2;1At expression was mediated by NH4+, gln and other amino acids.
Zhuo
D
D
Botany Department, University of British Columbia, Vancouver, Canada.
Okamoto
M
M
Vidmar
J J
JJ
Glass
A D
AD
D027321:Anion Transport Proteins; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D001693:Biological Transport, Active; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D000091285:Nitrate Transporters; D009566:Nitrates / Q000378:metabolism*; D010940:Plant Proteins; D018517:Plant Roots / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D027321:Anion Transport Proteins; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D000091285:Nitrate Transporters; D009566:Nitrates; D010940:Plant Proteins; C477335:NRT2.1 protein, Arabidopsis