Os01g0704100

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Annotated Information

 1、The gene name of High-affinity Nitrate Transporter is OsNRT2.3, it located on Chromosome 1.It's Genomic Sequence in NCBI is NC_008394.4. It is a protein coding gene.
 2、Pathways from Bio Systems:

Nitrate assimilation, organism-specific bio-system (from KEGG) Nitrate assimilation, conserved bio-system (from KEGG) Nitrogen metabolism, organism-specific bio-system (from KEGG) Nitrogen metabolism, organism-specific bio-system(from KEGG).

 3、General protein information 
 Preferred Names: Os01g0704100
 Names: hypothetical protein
 NP_001044003.1: Similar to Membrane transporter~contains Inter Pro domain(s): IPR001753~has GO asignment(s): GO:0003824, GO:0008152~supported by AK072215 

Function

  When the rice in a low nitrate supply environment , OsNRT2.3 plays an important role in nitrate and long distance transport from root to shoot.
  On the one hand, overexpression of OsNRT2.3 can not only improve the total dry matter's accumulation and translocation in the later stage, but also can significantly increase dry matter's translocation efficiency and contribution rate of transferred dry matter in rice. On the other hand, overexpression of OsNRT2.3 can not only increase the amount of nitrogen accumulation and nitrogen translocation amount, but also can significantly increase rice N translocation rate and nitrogen contribution rate in the later stage.
  OsNRT2.3 gene silencing could inhibit N03- transport to the shoot from underground, which leads to the accumulation of NO3- in rice roots, and thus indirectly down regulated OsNRT2.1/2.2 expression, eventually lead to reduced nitrate uptake in rice roots from the environment.

Expression

  In the field growth conditions, OsNRT2.3 mainly express in the root, it also express in the leaf and other parts in a low expression level. In the whole growing period, the amount of OsNRT2.3 expression in leaves increased with the growth of the plant, it reaches a maximum value in the vegetative growth to reproductive growth transition stage , then decrease to a relatively stable range. Rice protoplast subcellular localization experiments showed that OsNRT2.3 is transmembrane protein of plasma membrane localization, this is consistent with bioinformatics prediction results.
  OsNRT2.3aWas Localized to the Plasma Membrane
  To determine subcellular location, OsNRT2.3a was fused in frame with GFP and transiently expressed in rice protoplasts under the control of the cauliflower mosaic virus 35S promoter. Analyses ofOsNRT2.3a -GFP-expressing rice protoplast cells by confocal micros-copy showed that the green fluorescence was confined to the plasma membrane. Thus, OsNRT2.3a is a plasma membrane-localized nitrate transporter.
  OsNRT2.3aWas Mainly Expressed in Root Stelar Cells

Evolution

One gene OsNRT2.3 was mRNA spliced into OsNRT2.3a and OsNRT2.3b and OsNAR2.1 interacts with OsNRT2.1/2.2 and OsNRT2.3a to provide nitrate uptake. Using promoter-GUS reporter plants and semi-quantitative RT-PCR analyses, it was observed that OsNAR2.1 was expressed mainly in the root epidermal cells, differently from the five OsNRT2 genes. OsNAR2.1, OsNRT2.1, OsNRT2.2, and OsNRT2.3a were up-regulated by nitrate and suppressed by NH(4)(+) and high root temperature (37 °C). Expression of all these genes was increased by light or external sugar supply. Root transcripts of OsNRT2.3b and OsNRT2.4 were much less abundant and not affected by temperature. Expression of OsNRT2.3b was insensitive to the form of N supply. Expression of OsNRT2.4 responded to changes in auxin supply unlike all the other NRT2 genes. A region from position -311 to -1, relative to the translation start site in the promoter region of OsNAR2.1, was found to contain the cis-element(s) necessary for the nitrate-, but not light- and sugar-dependent activation. However, it was difficult to define a conserved cis-element in the promoters of the nitrate-regulated OsNRT2/OsNAR2 genes. The results imply distinct physiological functions for each OsNRT2 transporter, and differential regulation pathways by N and C status.

Labs working on this gene

State Key Laboratory of Crop Genetics and Ge rmplas m E nhancement a nd Ke y Laboratory of Plant Nutrition and F erti lization in L ow -Mid dle R each es of th e Yan gtze River, Ministry of Agriculture, Nanjing Agricultural University, N anjing 210095, China ; Disease a nd Stress Biology Department, J ohn Innes Center, N orwich NR4 7UH, U ni te d Kingdom

References

 1、Zhong Tang;Xiaorong Fan;Qing Li;Huimin Feng;Anthony J. Miller;Qirong Shen;Guohua Xu
 Knockdown of a Rice Stelar Nitrate Transporter Alters Long-Distance Translocation But Not Root Influx
 Plant Physiology, 2012, 160(4): 2052-2063
 2、The Rice Annotation Project Database (RAP-DB): 2008 update. Rice Annotation Project, et al. Nucleic Acids Res, 2008 Jan. PMID 18089549
 3、Curated genome annotation of Oryza sativa ssp. japonica and comparative genome analysis with Arabidopsis thaliana. Rice Annotation Project, et al. Genome Res, 2007 Feb. PMID 17210932
 4、The Rice Annotation Project Database (RAP-DB): hub for Oryza sativa ssp. japonica genome information. Ohyanagi H, et al. Nucleic Acids Res, 2006 Jan 1. PMID 16381971
 5、The map-based sequence of the rice genome. International Rice Genome Sequencing Project. Nature, 2005 Aug 11. PMID 16100779
 6、J Exp Bot. 2011 Apr;62(7):2319-32. doi: 10.1093/jxb/erq403. Epub 2011 Jan 10.Spatial expression and regulation of rice high-affinity nitrate transporters by nitrogen and carbon status. Feng H1, Yan M, Fan X, Li B, Shen Q, Miller AJ, Xu G.