Abstract
Rice has a preference for uptake of ammonium over nitrate and can use ammonium-N efficiently. Consequently, transporters mediating ammonium uptake have been extensively studied, but nitrate transporters have been largely ignored. Recently, some reports have shown that rice also has high capacity to acquire nitrate from growth medium, so understanding the nitrate transport system in rice roots is very important for improving N use efficiency in rice. The present study identified four putative NRT2 and two putative NAR2 genes that encode components of the high-affinity nitrate transport system (HATS) in the rice (Oryza sativa L. subsp. japonica cv. Nipponbare) genome. OsNRT2.1 and OsNRT2.2 share an identical coding region sequence, and their deduced proteins are closely related to those from mono-cotyledonous plants. The two NAR2 proteins are closely related to those from mono-cotyledonous plants as well. However, OsNRT2.3 and OsNRT2.4 are more closely related to Arabidopsis NRT2 proteins. Relative quantitative reverse transcription-polymerase chain reaction analysis showed that all of the six genes were rapidly upregulated and then downregulated in the roots of N-starved rice plants after they were re-supplied with 0.2 mM nitrate, but the response to nitrate differed among gene members. The results from phylogenetic tree, gene structure and expression analysis implied the divergent roles for the individual members of the rice NRT2 and NAR2 families. High-affinity nitrate influx rates associated with nitrate induction in rice roots were investigated and were found to be regulated by external pH. Compared with the nitrate influx rates at pH 6.5, alkaline pH (pH 8.0) inhibited nitrate influx, and acidic pH (pH 5.0) enhanced the nitrate influx in 1 h nitrate induced roots, but did not significantly affect that in 4 to 8 h nitrate induced roots.
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Claims 11
Claim · model-written summary
Four putative NRT2 and two putative NAR2 genes were identified.
- Taxon
- rice
Oryza sativae0 - Gene
- NRT2e0
- Outcome
- four putative NRT2 and two putative NAR2 genese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“identified four putative NRT2 and two putative NAR2 genes that encode components of the high-affinity nitrate transport system (HATS) in the rice (Oryza sativa L. subsp. japonica cv. Nipponbare) genome”
Claim · model-written summary
OsNRT2.1 and OsNRT2.2 share an identical coding region.
- Taxon
- RiceOryza sativat0
- Gene
- OsNRT2.1 and OsNRT2.2e0
- Outcome
- identical coding region sequencee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“OsNRT2.1 and OsNRT2.2 share an identical coding region sequence”
t0“Rice”
Claim · model-written summary
OsNRT2.1 and OsNRT2.2 proteins are close to monocot proteins.
- Taxon
- RiceOryza sativat0
- Gene
- OsNRT2.1 and OsNRT2.2e1
- Outcome
- closely related to those from mono-cotyledonous plantse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“their deduced proteins are closely related to those from mono-cotyledonous plants”
t0“Rice”
e1“OsNRT2.1 and OsNRT2.2”
Claim · model-written summary
NAR2 proteins are closely related to monocot proteins.
- Taxon
- RiceOryza sativat0
- Gene
- NAR2e0
- Outcome
- closely related to those from mono-cotyledonous plantse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The two NAR2 proteins are closely related to those from mono-cotyledonous plants”
t0“Rice”
Claim · model-written summary
OsNRT2.3 and OsNRT2.4 are more closely related to Arabidopsis NRT2 proteins.
- Taxon
- RiceOryza sativat0
- Gene
- OsNRT2.3 and OsNRT2.4e0
- Outcome
- more closely related to Arabidopsis NRT2 proteinse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“OsNRT2.3 and OsNRT2.4 are more closely related to Arabidopsis NRT2 proteins”
t0“Rice”
Claim · model-written summary
All six genes rose rapidly then declined after nitrate resupply.
- Taxon
- riceOryza sativae0
- Organ / stage
- rootse0
- Treatment
- re-supplied with 0.2 mM nitratee0
- Outcome
- all of the six genese0
- Direction
- upregulated and then downregulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“all of the six genes were rapidly upregulated and then downregulated in the roots of N-starved rice plants after they were re-supplied with 0.2 mM nitrate”
Claim · model-written summary
Nitrate response differed among gene members.
- Taxon
- RiceOryza sativat0
- Outcome
- response to nitratee0
- Direction
- differede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the response to nitrate differed among gene members”
t0“Rice”
Claim · model-written summary
The analyses implied divergent roles of rice NRT2 and NAR2 members.
- Taxon
- riceOryza sativae0
- Gene
- NRT2 and NAR2e0
- Outcome
- divergent rolese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“implied the divergent roles for the individual members of the rice NRT2 and NAR2 families”
Claim · model-written summary
Alkaline pH inhibited nitrate influx after one hour of induction.
- Taxon
- RiceOryza sativat0
- Treatment
- alkaline pH (pH 8.0)e0
- Outcome
- nitrate influxe0
- Direction
- inhibitede0
- Qualifier
- 1 h nitrate induced rootse0
- Comparator
- pH 6.5e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“alkaline pH (pH 8.0) inhibited nitrate influx, and acidic pH (pH 5.0) enhanced the nitrate influx in 1 h nitrate induced roots”
t0“Rice”
e1“Compared with the nitrate influx rates at pH 6.5”
Claim · model-written summary
Acidic pH enhanced nitrate influx after one hour of induction.
- Taxon
- RiceOryza sativat0
- Treatment
- acidic pH (pH 5.0)e0
- Outcome
- nitrate influxe0
- Direction
- enhancede0
- Qualifier
- 1 h nitrate induced rootse0
- Comparator
- pH 6.5e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“acidic pH (pH 5.0) enhanced the nitrate influx in 1 h nitrate induced roots”
t0“Rice”
e1“Compared with the nitrate influx rates at pH 6.5”
Claim · model-written summary
pH did not significantly affect influx after four to eight hours of induction.
- Taxon
- RiceOryza sativat0
- Treatment
- alkaline pH (pH 8.0)e1
- Outcome
- nitrate influxe3
- Direction
- did not significantly affecte0
- Qualifier
- 4 to 8 h nitrate induced rootse0
- Comparator
- pH 6.5e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“did not significantly affect that in 4 to 8 h nitrate induced roots”
t0“Rice”
e1“alkaline pH (pH 8.0)”
e2“Compared with the nitrate influx rates at pH 6.5”
e3“High-affinity nitrate influx rates associated with nitrate induction in rice roots”
The same questions in other papers
alkalinity · nutrient: content · Oryza sativa (rice)Positive and negative results
5 papers in the same direction as this paper · 4 in the opposite direction
- positive
- positive
- positive
6 papers more in this group
See all 10 papers →ph · nutrient: content · Oryza sativa (rice)Positive and negative results
5 papers in the same direction as this paper · 6 in the opposite direction
- negative
- negative
- no effect
8 papers more in this group
See all 12 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.