Abstract
High-affinity ammonium uptake in plant roots is mainly mediated by AMT1-type ammonium transporters, and their regulation varies depending on the plant species. In this study we aimed at characterizing AMT-mediated ammonium transport in maize, for which ammonium-based fertilizer is an important nitrogen (N) source. Two ammonium transporter genes, ZmAMT1;1a and ZmAMT1;3, were isolated from a maize root-specific cDNA library by functional complementation of an ammonium uptake-defective yeast mutant. Ectopic expression of both genes in an ammonium uptake-defective Arabidopsis mutant conferred high-affinity ammonium uptake capacities in roots with substrate affinities of 48 and 33 μM for ZmAMT1;1a and ZmAMT1;3, respectively. In situ hybridization revealed co-localization of both ZmAMT genes on the rhizodermis, suggesting an involvement in capturing ammonium from the rhizosphere. In N-deficient maize roots, influx increased significantly while ZmAMT expression did not. Ammonium resupply to N-deficient or nitrate-pre-cultured roots, however, rapidly enhanced both influx and ZmAMT transcript levels, revealing a substrate-inducible regulation of ammonium uptake. In conclusion, the two rhizodermis-localized transporters ZmAMT1;1a and ZmAMT1;3 are most probably the major components in the high-affinity transport system in maize roots. A particular regulatory feature is their persistent induction by ammonium rather than an up-regulation under N deficiency.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 10
Claim · model-written summary
ZmAMT1;1a and ZmAMT1;3 were isolated from a maize root cDNA library by complementation of a yeast uptake mutant.
Zea maysNot reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Two ammonium transporter genes, ZmAMT1;1a and ZmAMT1;3, were isolated from a maize root-specific cDNA library by functional complementation of an ammonium uptake-defective yeast mutant.”
Claim · model-written summary
Ectopic ZmAMT1;1a expression conferred high-affinity root ammonium uptake with substrate affinity 48 μM in the Arabidopsis mutant.
- Taxon
- Arabidopsis
Arabidopsise0 - Treatment
- Ectopic expressione0
- Gene
- ZmAMT1;1ae0
- Outcome
- high-affinity ammonium uptake capacities in rootse0
- Direction
- conferrede0
- Value
- 48e0
- Comparator
- ammonium uptake-defective Arabidopsis mutante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Schema note from the model: The shared unit μM follows the paired values 48 and 33 in the source sentence.
Verbatim
e0“Ectopic expression of both genes in an ammonium uptake-defective Arabidopsis mutant conferred high-affinity ammonium uptake capacities in roots with substrate affinities of 48 and 33 μM for ZmAMT1;1a and ZmAMT1;3, respectively.”
Claim · model-written summary
Ectopic ZmAMT1;3 expression conferred high-affinity root ammonium uptake with substrate affinity 33 μM in the Arabidopsis mutant.
- Taxon
- ArabidopsisArabidopsise0
- Treatment
- Ectopic expressione0
- Gene
- ZmAMT1;3e0
- Outcome
- high-affinity ammonium uptake capacities in rootse0
- Direction
- conferrede0
- Value
- 33 μMe0
- Comparator
- ammonium uptake-defective Arabidopsis mutante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Schema note from the model: Ectopic expression is in Arabidopsis, whereas the study centers on maize.
Verbatim
e0“Ectopic expression of both genes in an ammonium uptake-defective Arabidopsis mutant conferred high-affinity ammonium uptake capacities in roots with substrate affinities of 48 and 33 μM for ZmAMT1;1a and ZmAMT1;3, respectively.”
Claim · model-written summary
Both ZmAMT genes were co-localized on the maize rhizodermis.
- Organ / stage
- rhizodermise0
- Gene
- ZmAMTe0
- Outcome
- co-localization of both ZmAMT genes on the rhizodermise0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In situ hybridization revealed co-localization of both ZmAMT genes on the rhizodermis”
t0“Maize”
Claim · model-written summary
Ammonium influx increased significantly in nitrogen-deficient maize roots.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In N-deficient maize roots, influx increased significantly while ZmAMT expression did not.”
Claim · model-written summary
ZmAMT expression did not increase in nitrogen-deficient maize roots despite higher influx.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In N-deficient maize roots, influx increased significantly while ZmAMT expression did not.”
Claim · model-written summary
Ammonium resupply rapidly enhanced influx in nitrogen-deficient or nitrate-pre-cultured maize roots.
- Treatment
- Ammonium resupplye0
- Outcome
- influxe0
- Direction
- enhancede0
- Qualifier
- rapidlye0
- Comparator
- N-deficient or nitrate-pre-cultured rootse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ammonium resupply to N-deficient or nitrate-pre-cultured roots, however, rapidly enhanced both influx and ZmAMT transcript levels”
t0“Maize”
Claim · model-written summary
Ammonium resupply rapidly enhanced ZmAMT transcript levels in nitrogen-deficient or nitrate-pre-cultured maize roots.
- Treatment
- Ammonium resupplye0
- Gene
- ZmAMTe0
- Outcome
- ZmAMT transcript levelse0
- Direction
- enhancede0
- Qualifier
- rapidlye0
- Comparator
- N-deficient or nitrate-pre-cultured rootse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ammonium resupply to N-deficient or nitrate-pre-cultured roots, however, rapidly enhanced both influx and ZmAMT transcript levels”
t0“Maize”
Claim · model-written summary
The authors identify ZmAMT1;1a and ZmAMT1;3 as probable major components of high-affinity ammonium transport in maize roots.
- Organ / stage
- rootse0
- Gene
- ZmAMT1;1a and ZmAMT1;3e0
- Outcome
- major components in the high-affinity transport systeme0
- Qualifier
- most probablye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the two rhizodermis-localized transporters ZmAMT1;1a and ZmAMT1;3 are most probably the major components in the high-affinity transport system in maize roots.”
Claim · model-written summary
The authors conclude that these maize transporters show persistent induction by ammonium.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A particular regulatory feature is their persistent induction by ammonium”
t0“Maize”
The same questions in other papers
nitrogen · molecular: expression · Zea mays (maize)Positive and negative results
19 papers in the same direction as this paper · 5 in the opposite direction
- positive
- positive
- positive
21 papers more in this group
See all 25 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.