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https://hdl.handle.net/2440/34538
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Type: | Journal article |
Title: | Functional analysis of an Arabidopsis T-DNA "Knockout" of the high-affinity NH₄⁺ transporter AtAMT1;1¹ |
Other Titles: | Functional analysis of an Arabidopsis T-DNA "Knockout" of the high-affinity NH (4)(+) Transporter AtAMT1;1(1) |
Author: | Kaiser, B. Rawat, S. Siddiqi, M. Masle, J. Glass, A. |
Citation: | Plant Physiology, 2002; 130(3):1263-1275 |
Publisher: | Amer Soc Plant Physiologists |
Issue Date: | 2002 |
ISSN: | 0032-0889 1532-2548 |
Statement of Responsibility: | Brent N. Kaiser, Suman R. Rawat, M. Yaeesh Siddiqi, Josette Masle, and Anthony D.M. Glass |
Abstract: | NH4+ acquisition by plant roots is thought to involve members of the NH4+ transporter family (AMT) found in plants, yeast, bacteria, and mammals. In Arabidopsis, there are six AMT genes of which AtAMT1;1 demonstrates the highest affinity for NH4+. Ammonium influx into roots and AtAMT1;1 mRNA expression levels are highly correlated diurnally and when plant nitrogen (N) status is varied. To further investigate the involvement of AtAMT1;1 in high-affinity NH4+ influx, we identified a homozygous T-DNA mutant with disrupted AtAMT1;1 activity. Contrary to expectation, high-affinity 13NH4+ influx in the amt1;1:T-DNA mutant was similar to the wild type when grown with adequate N. Removal of N to increase AtAMT1;1 expression decreased high-affinity 13NH4+ influx in the mutant by 30% compared with wild-type plants, whereas low-affinity 13NH4+ influx (250 μm–10 mm NH4+) exceeded that of wild-type plants. In these N-deprived plants, mRNA copy numbers of root AtAMT1;3 and AtAMT2;1 mRNA were significantly more increased in the mutant than in wild-type plants. Under most growth conditions, amt1;1:T-DNA plants were indistinguishable from the wild type, however, leaf morphology was altered. However, when grown with NH4+ and sucrose, the mutant grew poorly and died. Our results are the first in planta evidence that AtAMT1;1 is a root NH4+ transporter and that redundancies within the AMT family may allow compensation for the loss of AtAMT1;1. |
Rights: | © 2002 American Society of Plant Biologists |
DOI: | 10.1104/pp.102.010843 |
Published version: | http://www.plantphysiol.org/cgi/content/abstract/130/3/1263?ck=nck |
Appears in Collections: | Agriculture, Food and Wine publications Aurora harvest 6 |
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