459 |
Entry URI |
http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u17026539i |
Entry name |
Loqué Dominique et al. 2006 Nov. Plant J. 48(4):522-34. |
Title |
Additive contribution of AMT1;1 and AMT1;3 to high-affinity ammonium uptake across the plasma membrane of nitrogen-deficient Arabidopsis roots. |
Authors |
Gazzarrini Sonia|Gojon Alain|Ishiyama Keiki|Kojima Soichi|Loqué Dominique|Takahashi Hideki|Wirth Judith|Yuan Lixing|von Wirén Nicolaus |
Abstract |
In Arabidopsis four root-expressed AMT genes encode functional ammonium transporters, which raises the question of their role in primary ammonium uptake. After pre-culturing under nitrogen-deficiency conditions, we quantified the influx of (15)N-labeled ammonium in T-DNA insertion lines and observed that the loss of either AMT1;1 or AMT1;3 led to a decrease in the high-affinity ammonium influx of approximately 30%. Under nitrogen-sufficient conditions the ammonium influx was lower in Columbia glabra compared with Wassilewskija (WS), and AMT1;1 did not contribute significantly to the ammonium influx in Col-gl. Ectopic expression of AMT1;3 under the control of a 35S promoter in either of the insertion lines amt1;3-1 or amt1;1-1 increased the ammonium influx above the level of their corresponding wild types. In transgenic lines carrying AMT-promoter-GFP constructs, the promoter activities of AMT1;1 and AMT1;3 were both upregulated under nitrogen-deficiency conditions and were localized to the rhizodermis, including root hairs. AMT gene-GFP fusions that were stably expressed under the control of their own promoters were localized to the plasma membrane. The double insertion line amt1;1-1amt1;3-1 showed a decreased sensitivity to the toxic ammonium analog methylammonium and a decrease in the ammonium influx of up to 70% relative to wild-type plants. These results suggest an additive contribution of AMT1;1 and AMT1;3 to the overall ammonium uptake capacity in Arabidopsis roots under nitrogen-deficiency conditions. |
Pubmed ID |
17026539 |
Journal |
The Plant journal |
Volume |
48 |
Issue |
4 |
Pages |
522-34 |
Publication date |
2006 Nov |
Num of phenotype gene |
0 |