Abstract
Nitrate uptake by the roots is under systemic feedback repression by high nitrogen (N) status of the whole plant. The NRT2.1 gene, which encodes a NO(3)(-) transporter involved in high-affinity root uptake, is a major target of this N signaling mechanism. Using transgenic Arabidopsis (Arabidopsis thaliana) plants expressing the pNRT2.1::LUC reporter gene (NL line), we performed a genetic screen to isolate mutants altered in the NRT2.1 response to high N provision. Three hni (for high nitrogen insensitive) mutants belonging to three genetic loci and related to single and recessive mutations were selected. Compared to NL plants, these mutants display reduced down-regulation of both NRT2.1 expression and high-affinity NO(3)(-) influx under repressive conditions. Split-root experiments demonstrated that this is associated with an almost complete suppression of systemic repression of pNRT2.1 activity by high N status of the whole plant. Other mechanisms related to N and carbon nutrition regulating NRT2.1 or involved in the control of root SO(4)(-) uptake by the plant sulfur status are not or are slightly affected. The hni mutations did not lead to significant changes in total N and NO(3)(-) contents of the tissues, indicating that hni mutants are more likely regulatory mutants rather than assimilatory mutants. Nevertheless, hni mutations induce changes in amino acid, organic acid, and sugars pools, suggesting a possible role of these metabolites in the control of NO(3)(-) uptake by the plant N status. Altogether, our data indicate that the three hni mutants define a new class of N signaling mutants specifically impaired in the systemic feedback repression of root NO(3)(-) uptake.
Abstract from the paper’s OpenAlex record; open copy licensed other-oa. 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
Three recessive hni mutants at three genetic loci were selected.
- Taxon
- Arabidopsis (Arabidopsis thaliana)
Arabidopsis thalianat0 - Material
- hni (for high nitrogen insensitive) mutantse0
- Outcome
- three genetic locie0
- Value
- Threee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Three hni (for high nitrogen insensitive) mutants belonging to three genetic loci and related to single and recessive mutations were selected.”
t0“Arabidopsis (Arabidopsis thaliana)”
Claim · model-written summary
The hni mutants showed reduced down-regulation of NRT2.1 expression compared with NL plants under repressive conditions.
- Taxon
- Arabidopsis (Arabidopsis thaliana)Arabidopsis thalianat0
- Material
- these mutantse0
- Treatment
- repressive conditionse0
- Gene
- NRT2.1e0
- Outcome
- NRT2.1 expressione0
- Direction
- reduced down-regulatione0
- Comparator
- NL plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to NL plants, these mutants display reduced down-regulation of both NRT2.1 expression and high-affinity NO(3)(-) influx under repressive conditions.”
t0“Arabidopsis (Arabidopsis thaliana)”
Claim · model-written summary
The hni mutants showed reduced down-regulation of high-affinity nitrate influx compared with NL plants.
- Taxon
- Arabidopsis (Arabidopsis thaliana)Arabidopsis thalianat0
- Material
- these mutantse0
- Treatment
- repressive conditionse0
- Outcome
- high-affinity NO(3)(-) influxe0
- Direction
- reduced down-regulatione0
- Comparator
- NL plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to NL plants, these mutants display reduced down-regulation of both NRT2.1 expression and high-affinity NO(3)(-) influx under repressive conditions.”
t0“Arabidopsis (Arabidopsis thaliana)”
Claim · model-written summary
The hni phenotype was associated with almost complete suppression of systemic repression of pNRT2.1 activity under high whole-plant nitrogen status.
- Taxon
- Arabidopsis (Arabidopsis thaliana)Arabidopsis thalianat0
- Treatment
- high N status of the whole plante0
- Gene
- pNRT2.1e0
- Outcome
- systemic repression of pNRT2.1 activitye0
- Direction
- suppressione0
- Qualifier
- almost completee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Split-root experiments demonstrated that this is associated with an almost complete suppression of systemic repression of pNRT2.1 activity by high N status of the whole plant.”
t0“Arabidopsis (Arabidopsis thaliana)”
Claim · model-written summary
Other nitrogen- and carbon-nutrition mechanisms regulating NRT2.1 were unaffected or slightly affected in the mutants.
- Taxon
- Arabidopsis (Arabidopsis thaliana)Arabidopsis thalianat0
- Gene
- NRT2.1e0
- Outcome
- Other mechanisms related to N and carbon nutrition regulating NRT2.1e0
- Direction
- not or are slightly affectede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Other mechanisms related to N and carbon nutrition regulating NRT2.1 or involved in the control of root SO(4)(-) uptake by the plant sulfur status are not or are slightly affected.”
t0“Arabidopsis (Arabidopsis thaliana)”
Claim · model-written summary
Control of root sulfate uptake by plant sulfur status was unaffected or slightly affected in the mutants.
- Taxon
- Arabidopsis (Arabidopsis thaliana)Arabidopsis thalianat0
- Outcome
- control of root SO(4)(-) uptake by the plant sulfur statuse0
- Direction
- not or are slightly affectede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Other mechanisms related to N and carbon nutrition regulating NRT2.1 or involved in the control of root SO(4)(-) uptake by the plant sulfur status are not or are slightly affected.”
t0“Arabidopsis (Arabidopsis thaliana)”
Claim · model-written summary
The hni mutations did not significantly change tissue total nitrogen or nitrate content.
- Taxon
- Arabidopsis (Arabidopsis thaliana)Arabidopsis thalianat0
- Material
- hni mutantse0
- Treatment
- hni mutationse0
- Outcome
- total N and NO(3)(-) contents of the tissuese0
- Direction
- did not lead to significant changese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The hni mutations did not lead to significant changes in total N and NO(3)(-) contents of the tissues, indicating that hni mutants are more likely regulatory mutants rather than assimilatory mutants.”
t0“Arabidopsis (Arabidopsis thaliana)”
Claim · model-written summary
The authors interpret hni mutants as regulatory rather than assimilatory mutants.
- Taxon
- Arabidopsis (Arabidopsis thaliana)Arabidopsis thalianat0
- Material
- hni mutantse0
- Outcome
- regulatory mutants rather than assimilatory mutantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The hni mutations did not lead to significant changes in total N and NO(3)(-) contents of the tissues, indicating that hni mutants are more likely regulatory mutants rather than assimilatory mutants.”
t0“Arabidopsis (Arabidopsis thaliana)”
Claim · model-written summary
The hni mutations changed amino acid, organic acid, and sugar pools.
- Taxon
- Arabidopsis (Arabidopsis thaliana)Arabidopsis thalianat0
- Treatment
- hni mutationse0
- Outcome
- amino acid, organic acid, and sugars poolse0
- Direction
- changese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nevertheless, hni mutations induce changes in amino acid, organic acid, and sugars pools, suggesting a possible role of these metabolites in the control of NO(3)(-) uptake by the plant N status.”
t0“Arabidopsis (Arabidopsis thaliana)”
Claim · model-written summary
The authors suggest these metabolite pools may participate in nitrogen-status control of nitrate uptake.
- Taxon
- Arabidopsis (Arabidopsis thaliana)Arabidopsis thalianat0
- Compound
- these metabolitese0
- Outcome
- control of NO(3)(-) uptake by the plant N statuse0
- Qualifier
- possible rolee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nevertheless, hni mutations induce changes in amino acid, organic acid, and sugars pools, suggesting a possible role of these metabolites in the control of NO(3)(-) uptake by the plant N status.”
t0“Arabidopsis (Arabidopsis thaliana)”
The same questions in other papers
loss of function · nutrient: content · Arabidopsis thaliana (thale cress)Positive and negative results
18 papers in the same direction as this paper · 7 in the opposite direction
- no effect
- positive
- positive
22 papers more in this group
See all 26 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.