Abstract
The high affinity nitrate transport system (HATS) plays an important role in rice nitrogen acquisition because, even under flooded anaerobic cultivation when NH(4)(+) dominates, significant nitrification occurs on the root surface. In the rice genome, four NRT2 and two NAR2 genes encoding HATS components have been identified. One gene OsNRT2.3 was mRNA spliced into OsNRT2.3a and OsNRT2.3b and OsNAR2.1 interacts with OsNRT2.1/2.2 and OsNRT2.3a to provide nitrate uptake. Using promoter-GUS reporter plants and semi-quantitative RT-PCR analyses, it was observed that OsNAR2.1 was expressed mainly in the root epidermal cells, differently from the five OsNRT2 genes. OsNAR2.1, OsNRT2.1, OsNRT2.2, and OsNRT2.3a were up-regulated by nitrate and suppressed by NH(4)(+) and high root temperature (37 °C). Expression of all these genes was increased by light or external sugar supply. Root transcripts of OsNRT2.3b and OsNRT2.4 were much less abundant and not affected by temperature. Expression of OsNRT2.3b was insensitive to the form of N supply. Expression of OsNRT2.4 responded to changes in auxin supply unlike all the other NRT2 genes. A region from position -311 to -1, relative to the translation start site in the promoter region of OsNAR2.1, was found to contain the cis-element(s) necessary for the nitrate-, but not light- and sugar-dependent activation. However, it was difficult to define a conserved cis-element in the promoters of the nitrate-regulated OsNRT2/OsNAR2 genes. The results imply distinct physiological functions for each OsNRT2 transporter, and differential regulation pathways by N and C status.
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Claims 13
Claim · model-written summary
OsNAR2.1 was mainly expressed in root epidermal cells, unlike the five OsNRT2 genes.
- Taxon
- rice
Oryza sativat0 - Organ / stage
- root epidermal cellse0
- Gene
- OsNAR2.1e0
- Outcome
- expressed mainly in the root epidermal cellse0
- Comparator
- five OsNRT2 genese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“OsNAR2.1 was expressed mainly in the root epidermal cells, differently from the five OsNRT2 genes.”
t0“rice”
Claim · model-written summary
Nitrate up-regulated OsNAR2.1, OsNRT2.1, OsNRT2.2 and OsNRT2.3a.
- Taxon
- riceOryza sativat0
- Treatment
- nitratee0
- Gene
- OsNAR2.1, OsNRT2.1, OsNRT2.2, and OsNRT2.3ae0
- Outcome
- OsNAR2.1, OsNRT2.1, OsNRT2.2, and OsNRT2.3ae0
- Direction
- up-regulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“OsNAR2.1, OsNRT2.1, OsNRT2.2, and OsNRT2.3a were up-regulated by nitrate and suppressed by NH(4)(+) and high root temperature (37 °C).”
t0“rice”
Claim · model-written summary
NH(4)(+) suppressed OsNAR2.1, OsNRT2.1, OsNRT2.2 and OsNRT2.3a.
- Taxon
- riceOryza sativat0
- Treatment
- NH(4)(+)e0
- Outcome
- OsNAR2.1, OsNRT2.1, OsNRT2.2, and OsNRT2.3ae0
- Direction
- suppressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“OsNAR2.1, OsNRT2.1, OsNRT2.2, and OsNRT2.3a were up-regulated by nitrate and suppressed by NH(4)(+) and high root temperature (37 °C).”
t0“rice”
Claim · model-written summary
High root temperature of 37 °C suppressed OsNAR2.1, OsNRT2.1, OsNRT2.2 and OsNRT2.3a.
- Taxon
- riceOryza sativat0
- Treatment
- high root temperature (37 °C)e0
- Outcome
- OsNAR2.1, OsNRT2.1, OsNRT2.2, and OsNRT2.3ae0
- Direction
- suppressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“OsNAR2.1, OsNRT2.1, OsNRT2.2, and OsNRT2.3a were up-regulated by nitrate and suppressed by NH(4)(+) and high root temperature (37 °C).”
t0“rice”
Claim · model-written summary
Light increased expression of these nitrate-transporter genes.
- Taxon
- riceOryza sativat0
- Treatment
- lighte0
- Outcome
- Expression of all these genese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of all these genes was increased by light or external sugar supply.”
t0“rice”
Claim · model-written summary
External sugar supply increased expression of these genes.
- Taxon
- riceOryza sativat0
- Treatment
- external sugar supplye0
- Outcome
- Expression of all these genese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of all these genes was increased by light or external sugar supply.”
t0“rice”
Claim · model-written summary
Root transcripts of OsNRT2.3b and OsNRT2.4 were much less abundant.
- Taxon
- riceOryza sativat0
- Organ / stage
- Roote0
- Outcome
- Root transcripts of OsNRT2.3b and OsNRT2.4e0
- Direction
- much less abundante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root transcripts of OsNRT2.3b and OsNRT2.4 were much less abundant and not affected by temperature.”
t0“rice”
Claim · model-written summary
Temperature did not affect root transcripts of OsNRT2.3b and OsNRT2.4.
- Taxon
- riceOryza sativat0
- Treatment
- temperaturee0
- Outcome
- Root transcripts of OsNRT2.3b and OsNRT2.4e0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root transcripts of OsNRT2.3b and OsNRT2.4 were much less abundant and not affected by temperature.”
t0“rice”
Claim · model-written summary
OsNRT2.3b expression was insensitive to nitrogen-supply form.
- Taxon
- riceOryza sativat0
- Treatment
- form of N supplye0
- Outcome
- Expression of OsNRT2.3be0
- Direction
- insensitivee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of OsNRT2.3b was insensitive to the form of N supply.”
t0“rice”
Claim · model-written summary
OsNRT2.4 expression responded to auxin supply unlike other NRT2 genes.
- Taxon
- riceOryza sativat0
- Treatment
- auxin supplye0
- Outcome
- Expression of OsNRT2.4e0
- Comparator
- all the other NRT2 genese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of OsNRT2.4 responded to changes in auxin supply unlike all the other NRT2 genes.”
t0“rice”
Claim · model-written summary
The OsNAR2.1 promoter region -311 to -1 contained elements necessary for nitrate-dependent activation, but not light- or sugar-dependent activation.
- Taxon
- riceOryza sativat0
- Gene
- OsNAR2.1e0
- Outcome
- activatione0
- Qualifier
- region from position -311 to -1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A region from position -311 to -1, relative to the translation start site in the promoter region of OsNAR2.1, was found to contain the cis-element(s) necessary for the nitrate-, but not light- and sugar-dependent activation.”
t0“rice”
Claim · model-written summary
A conserved cis-element was difficult to define in nitrate-regulated OsNRT2/OsNAR2 promoters.
- Taxon
- riceOryza sativat0
- Gene
- OsNRT2/OsNAR2e0
- Outcome
- difficult to define a conserved cis-elemente0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it was difficult to define a conserved cis-element in the promoters of the nitrate-regulated OsNRT2/OsNAR2 genes.”
t0“rice”
Claim · model-written summary
The results implied distinct transporter physiological functions and differential regulation by nitrogen and carbon status.
- Taxon
- riceOryza sativat0
- Gene
- OsNRT2e0
- Outcome
- distinct physiological functionse0
- Qualifier
- differential regulation pathways by N and C statuse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The results imply distinct physiological functions for each OsNRT2 transporter, and differential regulation pathways by N and C status.”
t0“rice”
The same questions in other papers
nitrogen · molecular: expression · Oryza sativa (rice)Positive and negative results
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