Abstract
BACKGROUND AND AIMS: Nitric oxide (NO) has been demonstrated to stimulate the activity of nitrate reductase (NR) in plant roots supplied with a low level of nitrate, and to affect proteins differently, depending on the ratio of NO to the level of protein. Nitrate has been suggested to regulate the level of NO in plants. This present study examined interactive effects of NO and nitrate level on NR activity in roots of tomato (Solanum lycocarpum). METHODS: NR activity, mRNA level of NR gene and concentration of NR protein in roots fed with 0.5 mM or 5 mM nitrate and treated with the NO donors, sodium nitroprusside (SNP) and diethylamine NONOate sodium (NONOate), and the NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (cPTIO), were measured in 25-d-old seedlings. KEY RESULTS: Addition of SNP and NONOate enhanced but cPTIO decreased NR activity in the roots fed with 0.5 mm nitrate. The opposite was true for the roots fed with 5 mM nitrate. However, the mRNA level of the NR gene and the protein concentration of NR enzyme in the roots were not affected by SNP treatment, irrespective of nitrate pre-treatment. Nevertheless, a low rate of NO gas increased while cPTIO decreased the NR activities of the enzyme extracts from the roots at both nitrate levels. Increasing the rate of NO gas further increased NR activity in the enzyme extracts of the roots fed with 0.5 mM nitrate but decreased it when 5 mM nitrate was supplied. Interestingly, the stimulative effect of NO gas on NR activity could be reversed by NO removal through N(2) flushing in the enzyme extracts from the roots fed with 0.5 mM nitrate but not from those with 5 mM nitrate. CONCLUSIONS: The effects of NO on NR activity in tomato roots depend on levels of nitrate supply, and probably result from direct interactions between NO and NR protein.
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Claims 11
Claim · model-written summary
SNP and NONOate enhanced nitrate reductase activity in tomato roots fed 0.5 mM nitrate.
- Taxon
- tomato
Solanum lycopersicumt0 - Treatment
- SNP and NONOatee1
- Outcome
- NR activitye1
- Direction
- enhancede1
- Qualifier
- 0.5 mm nitratee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“roots of tomato (Solanum lycocarpum)”
e1“Addition of SNP and NONOate enhanced but cPTIO decreased NR activity in the roots fed with 0.5 mm nitrate”
Claim · model-written summary
cPTIO decreased nitrate reductase activity in tomato roots fed 0.5 mM nitrate.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- cPTIOe1
- Outcome
- NR activitye1
- Direction
- decreasede1
- Qualifier
- 0.5 mm nitratee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“roots of tomato (Solanum lycocarpum)”
e1“Addition of SNP and NONOate enhanced but cPTIO decreased NR activity in the roots fed with 0.5 mm nitrate”
Claim · model-written summary
At 5 mM nitrate, SNP and NONOate had the opposite effect on nitrate reductase activity in tomato roots.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- SNP and NONOatee1
- Outcome
- NR activitye1
- Direction
- oppositee2
- Qualifier
- 5 mM nitratee2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“roots of tomato (Solanum lycocarpum)”
e1“Addition of SNP and NONOate enhanced but cPTIO decreased NR activity in the roots fed with 0.5 mm nitrate”
e2“The opposite was true for the roots fed with 5 mM nitrate”
Claim · model-written summary
SNP did not change NR gene mRNA level or NR protein concentration in tomato roots regardless of nitrate pre-treatment.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- SNP treatmente3
- Gene
- NR genee3
- Outcome
- the mRNA level of the NR gene and the protein concentration of NR enzymee3
- Direction
- not affectede3
- Qualifier
- irrespective of nitrate pre-treatmente3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“roots of tomato (Solanum lycocarpum)”
e3“the mRNA level of the NR gene and the protein concentration of NR enzyme in the roots were not affected by SNP treatment, irrespective of nitrate pre-treatment”
Claim · model-written summary
A low rate of NO gas increased nitrate reductase activity in tomato root extracts at both nitrate levels.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- low rate of NO gase4
- Outcome
- NR activities of the enzyme extracts from the rootse4
- Direction
- increasede4
- Qualifier
- at both nitrate levelse4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“roots of tomato (Solanum lycocarpum)”
e4“a low rate of NO gas increased while cPTIO decreased the NR activities of the enzyme extracts from the roots at both nitrate levels”
Claim · model-written summary
cPTIO decreased nitrate reductase activity in tomato root extracts at both nitrate levels.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- cPTIOe4
- Outcome
- NR activities of the enzyme extracts from the rootse4
- Direction
- decreasede4
- Qualifier
- at both nitrate levelse4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“roots of tomato (Solanum lycocarpum)”
e4“a low rate of NO gas increased while cPTIO decreased the NR activities of the enzyme extracts from the roots at both nitrate levels”
Claim · model-written summary
Increasing the NO gas rate further increased nitrate reductase activity in tomato root extracts fed 0.5 mM nitrate.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- Increasing the rate of NO gase5
- Outcome
- NR activitye5
- Direction
- further increasede5
- Qualifier
- 0.5 mM nitratee5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“roots of tomato (Solanum lycocarpum)”
e5“Increasing the rate of NO gas further increased NR activity in the enzyme extracts of the roots fed with 0.5 mM nitrate but decreased it when 5 mM nitrate was supplied”
Claim · model-written summary
Increasing the NO gas rate decreased nitrate reductase activity in tomato root extracts fed 5 mM nitrate.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- Increasing the rate of NO gase5
- Outcome
- NR activitye5
- Direction
- decreasede5
- Qualifier
- 5 mM nitrate was suppliede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“roots of tomato (Solanum lycocarpum)”
e5“Increasing the rate of NO gas further increased NR activity in the enzyme extracts of the roots fed with 0.5 mM nitrate but decreased it when 5 mM nitrate was supplied”
Claim · model-written summary
NO removal by N2 flushing reversed the stimulative effect of NO gas on nitrate reductase activity in root extracts at 0.5 mM nitrate.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- NO removal through N(2) flushinge6
- Outcome
- stimulative effect of NO gas on NR activitye6
- Direction
- could be reversede6
- Qualifier
- 0.5 mM nitratee6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“roots of tomato (Solanum lycocarpum)”
e6“the stimulative effect of NO gas on NR activity could be reversed by NO removal through N(2) flushing in the enzyme extracts from the roots fed with 0.5 mM nitrate”
Claim · model-written summary
NO removal by N2 flushing did not reverse the stimulative effect of NO gas on nitrate reductase activity in root extracts at 5 mM nitrate.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- NO removal through N(2) flushinge6
- Outcome
- stimulative effect of NO gas on NR activitye6
- Direction
- but note7
- Qualifier
- 5 mM nitratee7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“roots of tomato (Solanum lycocarpum)”
e6“the stimulative effect of NO gas on NR activity could be reversed by NO removal through N(2) flushing in the enzyme extracts from the roots fed with 0.5 mM nitrate”
e7“but not from those with 5 mM nitrate”
Claim · model-written summary
The effects of NO on nitrate reductase activity in tomato roots depend on nitrate supply level and probably result from direct NO-NR protein interactions.
- Taxon
- tomatoSolanum lycopersicume7
- Gene
- NR proteine7
- Outcome
- effects of NO on NR activitye7
- Qualifier
- probably result from direct interactions between NO and NR proteine7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“The effects of NO on NR activity in tomato roots depend on levels of nitrate supply, and probably result from direct interactions between NO and NR protein”
The same questions in other papers
sodium nitroprusside · physiology: enzyme activity · Solanum lycopersicum (tomato)Positive and negative results
1 paper in the same direction as this paper · 4 in the opposite direction
- positive
- positive
- positive
2 papers more in this group
See all 6 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.