Regulation of the high-affinity ammonium transporter (BnAMT1;2) in the leaves of Brassica napus by nitrogen status

Regulation of the high-affinity ammonium transporter (BnAMT1;2) in the leaves of Brassica napus... Substantial concentrations of NH4 + are found in the apoplast of the leaves of Brassica napus. Physiological studies on isolated mesophyll protoplasts with 15NH4 + revealed the presence of a high-affinity ammonium transporter that shared physiological similarity to the high-affinity NH4 + transporters in Arabidopsis thaliana (AtAMT1;3). PCR techniques were used to isolate a full-length clone of a B. napus homologue of AMT1 from shoot mRNA which showed 97% similarity to AtAMT1;3. The full-length cDNA when cloned into the yeast expression vector pFL61 was able to complement a yeast mutant unable to grow on media with NH4 + as the sole nitrogen source. Regulatory studies with detached leaves revealed a stimulation of both NH4 + uptake and expression of mRNA when the leaves were supplied with increasing concentrations of NH4 +. Withdrawal of NH4 + supply for up to 96 h had little effect on mRNA expression or NH4 + uptake; however, plants grown continuously at high NH4 + levels exhibited decreased mRNA expression. BnAMT1;2mRNA expression was highest when NH4 + was supplied directly to the leaf and lowest when either glutamine or glutamate was supplied to the leaves, which directly paralleled chloroplastic glutamine synthetase (GS2) activity in the same leaves. These results provide tentative evidence that BnAMT1;2may be regulated by similar mechanisms to GS2 in leaves. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Plant Molecular Biology Springer Journals

Regulation of the high-affinity ammonium transporter (BnAMT1;2) in the leaves of Brassica napus by nitrogen status

Loading next page...
 
/lp/springer_journal/regulation-of-the-high-affinity-ammonium-transporter-bnamt1-2-in-the-aL08QTF3BT
Publisher
Springer Journals
Copyright
Copyright © 2002 by Kluwer Academic Publishers
Subject
Life Sciences; Biochemistry, general; Plant Sciences; Plant Pathology
ISSN
0167-4412
eISSN
1573-5028
D.O.I.
10.1023/A:1015549115471
Publisher site
See Article on Publisher Site

Abstract

Substantial concentrations of NH4 + are found in the apoplast of the leaves of Brassica napus. Physiological studies on isolated mesophyll protoplasts with 15NH4 + revealed the presence of a high-affinity ammonium transporter that shared physiological similarity to the high-affinity NH4 + transporters in Arabidopsis thaliana (AtAMT1;3). PCR techniques were used to isolate a full-length clone of a B. napus homologue of AMT1 from shoot mRNA which showed 97% similarity to AtAMT1;3. The full-length cDNA when cloned into the yeast expression vector pFL61 was able to complement a yeast mutant unable to grow on media with NH4 + as the sole nitrogen source. Regulatory studies with detached leaves revealed a stimulation of both NH4 + uptake and expression of mRNA when the leaves were supplied with increasing concentrations of NH4 +. Withdrawal of NH4 + supply for up to 96 h had little effect on mRNA expression or NH4 + uptake; however, plants grown continuously at high NH4 + levels exhibited decreased mRNA expression. BnAMT1;2mRNA expression was highest when NH4 + was supplied directly to the leaf and lowest when either glutamine or glutamate was supplied to the leaves, which directly paralleled chloroplastic glutamine synthetase (GS2) activity in the same leaves. These results provide tentative evidence that BnAMT1;2may be regulated by similar mechanisms to GS2 in leaves.

Journal

Plant Molecular BiologySpringer Journals

Published: Oct 13, 2004

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off