Journal of Experimental Botany, Vol. 53, No. 370, pp. 835-844,
April 15, 2002
© 2002 Oxford University Press
Original Papers |
The Arabidopsis dual-affinity nitrate transporter gene AtNRT1.1 (CHL1) is regulated by auxin in both shoots and roots
Section of Cell and Developmental Biology, Division of Biology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0116, USA
The AtNRT1.1 (CHL1) gene of Arabidopsis encodes a dual-affinity nitrate transporter and contributes to both low and high affinity nitrate uptake. Localization studies have shown that CHL1 expression is preferentially targeted to nascent organs and growing regions of roots and shoots in Arabidopsis. In roots, CHL1 expression is concentrated in the tips of primary and lateral roots and is activated during lateral root initiation. In shoots, strong CHL1 expression is found in young leaves and developing flower buds. These findings suggest that CHL1 expression might be regulated by a growth signal such as the phytohormone auxin. To test this, auxin regulation of CHL1 was examined. Using transgenic Arabidopsis plants containing CHL1::GUS/GFP DNA constructs, it was found that treatment with exogenous auxin or introduction of the auxin overproducing mutations (yucca and rooty) resulted in a strong increase in CHL1::GUS/GFP signals in roots and leaves. When mature roots were treated with auxin to induce lateral root formation, CHL1::GFP signals were dramatically enhanced in dividing pericycle cells and throughout primordia development. RNA blot analysis showed that CHL1 mRNA levels in whole seedlings increase within 30 min of auxin treatment. The distribution of CHL1 expression in Arabidopsis roots and shoots was found to be similar to that of DR5::GUS, a synthetic, auxin-responsive gene. These results indicate that auxin acts as an important signal regulating CHL1 expression and contributes to the targeting of CHL1 expression to nascent organs and root tips in Arabidopsis.
Key words: Arabidopsis, AtNRT1.1, auxin, CHL1, nitrate transport.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  R. Wang, X. Xing, Y. Wang, A. Tran, and N. M. Crawford A Genetic Screen for Nitrate Regulatory Mutants Captures the Nitrate Transporter Gene NRT1.1 Plant Physiology, September 1, 2009; 151(1): 472 - 478. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Rubio, A. Linares-Rueda, M. J. Garcia-Sanchez, and J. A. Fernandez Physiological evidence for a sodium-dependent high-affinity phosphate and nitrate transport at the plasma membrane of leaf and root cells of Zostera marina L. J. Exp. Bot., February 1, 2005; 56(412): 613 - 622. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. L. Jeong, H. Jiang, H.-S. Chen, C.-J. Tsai, and S. A. Harding Metabolic Profiling of the Sink-to-Source Transition in Developing Leaves of Quaking Aspen Plant Physiology, October 1, 2004; 136(2): 3364 - 3375. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Rampey, S. LeClere, M. Kowalczyk, K. Ljung, G. Sandberg, and B. Bartel A Family of Auxin-Conjugate Hydrolases That Contributes to Free Indole-3-Acetic Acid Levels during Arabidopsis Germination Plant Physiology, June 1, 2004; 135(2): 978 - 988. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Loque, P. Tillard, A. Gojon, and M. Lepetit Gene Expression of the NO3- Transporter NRT1.1 and the Nitrate Reductase NIA1 Is Repressed in Arabidopsis Roots by NO2-, the Product of NO3- Reduction Plant Physiology, June 1, 2003; 132(2): 958 - 967. [Abstract] [Full Text] [PDF]
|
|