Nitrate transport in plants: which gene and which control?
Nitrate uptake by root cells is a key step of nitrogen metabolism and has been widely studied at the physiological level and, more recently, at the molecular level. Two classes of genes, NRT1 and NRT2, have been found to be potentially involved in the high and low affinity nitrate transport systems (HATS and LATS, respectively). The complexity of the molecular basis of nitrate uptake has been enhanced by the finding that in many plants both NRT1 and NRT2 classes are represented by multigene families. Furthermore, recent studies demonstrate that the control mechanisms that lead to an active protein at the plasma membrane act on gene transcription, modulating the steady-state levels of mRNA, and on the activation of the protein, possibly by a phosphorylation/dephosphorylation process. This is a review of recent progress in the characterization of the NRT2 nitrate transporters, the composition of this family in Arabidopsis, their possible role in nitrate acquisition, and some aspects of their regulation in plants.
Orsel
Mathilde
M
Unité de la Nutrition Azotée des Plantes, INRA, route de St Cyr, 78026 Versailles cedex, France.
Filleur
Sophie
S
Fraisier
Vincent
V
Daniel-Vedele
Françoise
F
D000595:Amino Acid Sequence; D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001692:Biological Transport / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D000091285:Nitrate Transporters; D009566:Nitrates / Q000378:metabolism*; D010940:Plant Proteins; D018517:Plant Roots / Q000235:genetics / Q000502:physiology; D010944:Plants / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D027321:Anion Transport Proteins; D029681:Arabidopsis Proteins; D000091285:Nitrate Transporters; D009566:Nitrates; D010940:Plant Proteins; C101492:NRT1.1 protein, Arabidopsis; C477335:NRT2.1 protein, Arabidopsis