The Arabidopsis ATNRT2.7 nitrate transporter controls nitrate content in seeds.
In higher plants, nitrate is taken up by root cells where Arabidopsis thaliana NITRATE TRANSPORTER2.1 (ATNRT2.1) chiefly acts as the high-affinity nitrate uptake system. Nitrate taken up by the roots can then be translocated from the root to the leaves and the seeds. In this work, the function of the ATNRT2.7 gene, one of the seven members of the NRT2 family in Arabidopsis, was investigated. High expression of the gene was detected in reproductive organs and peaked in dry seeds. beta-Glucuronidase or green fluorescent protein reporter gene expression driven by the ATNRT2.7 promoter confirmed this organ specificity. We assessed the capacity of ATNRT2.7 to transport nitrate in Xenopus laevis oocytes or when it is expressed ectopically in mutant plants deficient in nitrate transport. We measured the impact of an ATNRT2.7 mutation and found no difference from the wild type during vegetative development. By contrast, seed nitrate content was affected by overexpression of ATNRT2.7 or a mutation in the gene. Finally, we showed that this nitrate transporter protein was localized to the vacuolar membrane. Our results demonstrate that ATNRT2.7 plays a specific role in nitrate accumulation in the seed.
Chopin
Franck
F
Institut National de la Recherche Agronomique, Institut Jean-Pierre Bourgin, Unité de la Nutrition Azotée des Plantes, F-78000 Versailles, France.
Orsel
Mathilde
M
Dorbe
Marie-France
MF
Chardon
Fabien
F
Truong
Hoai-Nam
HN
Miller
Anthony J
AJ
Krapp
Anne
A
Daniel-Vedele
Françoise
F
D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D005838:Genotype; D018525:Germination; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007700:Kinetics; D009154:Mutation / Q000235:genetics; D009566:Nitrates / Q000378:metabolism*; D010802:Phylogeny; D012639:Seeds / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
D027321:Anion Transport Proteins; D029681:Arabidopsis Proteins; C523536:NRT2.7 protein, Arabidopsis; D009566:Nitrates; D049452:Green Fluorescent Proteins