Abstract
The expression of the tobacco genes encoding the ammonium-assimilating enzymes plastidic glutamine synthetase (GS-2) or ferredoxin-dependent glutamate synthase (Fd-GOGAT) was examined in relation to the rates of two major ammonium-producing processes in leaves, i.e. nitrate reduction and photorespiration. Impairment of nitrate reduction induced by the application of tungstate, a molybdate analogue inhibiting nitrate reductase (NR), resulted in an increase in the NR and the nitrite reductase (NiR) mRNA pools. It is shown that this effect could in part be reversed by the application of ammonium. These results support negative regulation by nitrate-derived N-metabolites of both the NR and NiR mRNA abundance. Both the GS-2 and the Fd-GOGAT transcript level and the corresponding enzymatic activities remained largely unaffected by impairment of nitrate reduction, suggesting that both GS-2 and Fd-GOGAT gene expression are not under the control by end products of nitrogen assimilation. Growth of tobacco at a CO2 partial pressure sufficiently high to suppress photorespiration (300 Pa CO2 had no effect on either the GS-2 or Fd-GOGAT transcript levels. It is concluded that the rate of photorespiratory ammonium production does not exert a metabolic control on GS-2 or Fd-GOGAT gene expression.
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Claims 6
Claim · model-written summary
Tungstate impairment of nitrate reduction increased NR mRNA.
- Taxon
- tobacco
Nicotiana tabacumt0 - Treatment
- application of tungstatee0
- Gene
- NRe0
- Outcome
- NRe0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Impairment of nitrate reduction induced by the application of tungstate, a molybdate analogue inhibiting nitrate reductase (NR), resulted in an increase in the NR and the nitrite reductase (NiR) mRNA pools”
t0“tobacco genes”
Claim · model-written summary
Tungstate impairment of nitrate reduction increased NiR mRNA.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- application of tungstatee0
- Gene
- NiRe0
- Outcome
- nitrite reductase (NiR) mRNA poolse0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Impairment of nitrate reduction induced by the application of tungstate, a molybdate analogue inhibiting nitrate reductase (NR), resulted in an increase in the NR and the nitrite reductase (NiR) mRNA pools”
t0“tobacco genes”
Claim · model-written summary
Ammonium partly reversed the tungstate induced mRNA response.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- application of ammoniume0
- Outcome
- this effecte0
- Direction
- reversede0
- Qualifier
- in parte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this effect could in part be reversed by the application of ammonium”
t0“tobacco genes”
Claim · model-written summary
GS-2 and Fd-GOGAT transcripts and enzyme activities were largely unaffected by impaired nitrate reduction.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- impairment of nitrate reductione0
- Gene
- GS-2e0
- Outcome
- transcript level and the corresponding enzymatic activitiese0
- Direction
- largely unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both the GS-2 and the Fd-GOGAT transcript level and the corresponding enzymatic activities remained largely unaffected by impairment of nitrate reduction”
t0“tobacco genes”
Claim · model-written summary
High CO2 suppression of photorespiration did not change GS-2 transcripts.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Growth of tobacco at a CO2 partial pressure sufficiently high to suppress photorespiration (300 Pa CO2 had no effect on either the GS-2 or Fd-GOGAT transcript levels”
Claim · model-written summary
High CO2 suppression of photorespiration did not change Fd-GOGAT transcripts.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- 300 Pa CO2e0
- Gene
- Fd-GOGATe0
- Outcome
- Fd-GOGAT transcript levelse0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Growth of tobacco at a CO2 partial pressure sufficiently high to suppress photorespiration (300 Pa CO2 had no effect on either the GS-2 or Fd-GOGAT transcript levels”
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See all 9 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.