Abstract
Oxalate is widely distributed and serves various functional roles in plants. However, its biosynthetic pathway and regulatory mechanisms remain poorly defined. In this study, we further investigated the mechanism of oxalate accumulation using rice (Oryza sativa) CRISPR-Cas9-generated nitrate reductase (NR) and nitrite reductase (NiR) mutants, combined with different treatments. Both NR and NiR mutants exhibited significantly reduced oxalate levels. The reduced oxalate in NR and NiR mutants was restored by nitrite and nitrate, respectively, whereas ammonium had no effect, indicating that both nitrate and nitrite reduction, rather than the subsequent ammonium assimilation, are involved in modulating oxalate accumulation in rice. Furthermore, various organic acids, including glycolate, glyoxylate, glycerate, and oxaloacetate, markedly stimulated oxalate content. Transcriptomic and metabolomic analyses revealed that oxalate levels were closely and positively associated with the expression of glycolytic and tricarboxylic acid (TCA) cycle genes and the content of their intermediate metabolites. Treatment with glycolytic intermediates (phosphoenolpyruvate (PEP) and 3-phosphoglycerate (3PGA)) and inhibitors (iodoacetate (IOA)and 3-bromopyruvate (BrPA)) further confirmed that glycolysis drives oxalate synthesis in rice. Nicotinamide (NAM), a NAD precursor, also restored the oxalate content, suggesting that NAD/NADH may play a mediatory role in oxalate regulation through both nitrate and nitrite reduction. Collectively, our results demonstrate that oxalate accumulation is intimately associated with glycolysis in rice, rather than with photorespiration, which instead regulates oxalate accumulation indirectly via the glycerate-mediated impact on glycolysis..
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. 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 11
Claim · model-written summary
NR mutants had significantly reduced oxalate.
- Taxon
- rice
Oryza sativat1 - Material
- NRe0
- Outcome
- oxalate levelse0
- Direction
- reducede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both NR and NiR mutants exhibited significantly reduced oxalate levels.”
t1“Rice”
Claim · model-written summary
NiR mutants had significantly reduced oxalate.
- Taxon
- riceOryza sativat1
- Material
- NiRe0
- Outcome
- oxalate levelse0
- Direction
- reducede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both NR and NiR mutants exhibited significantly reduced oxalate levels.”
t1“Rice”
Claim · model-written summary
Nitrite restored reduced oxalate in NR mutants.
- Taxon
- riceOryza sativat1
- Material
- NRe0
- Treatment
- nitritee0
- Outcome
- oxalatee0
- Direction
- restorede0
- Comparator
- reduced oxalatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The reduced oxalate in NR and NiR mutants was restored by nitrite and nitrate, respectively, whereas ammonium had no effect”
t1“Rice”
Claim · model-written summary
Nitrate restored reduced oxalate in NiR mutants.
- Taxon
- riceOryza sativat1
- Material
- NiRe0
- Treatment
- nitratee0
- Outcome
- oxalatee0
- Direction
- restorede0
- Comparator
- reduced oxalatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The reduced oxalate in NR and NiR mutants was restored by nitrite and nitrate, respectively, whereas ammonium had no effect”
t1“Rice”
Claim · model-written summary
Ammonium had no effect on reduced oxalate.
- Taxon
- riceOryza sativat1
- Treatment
- ammoniume0
- Outcome
- oxalatee0
- Direction
- no effecte0
- Comparator
- reduced oxalatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The reduced oxalate in NR and NiR mutants was restored by nitrite and nitrate, respectively, whereas ammonium had no effect”
t1“Rice”
Claim · model-written summary
Glycolate, glyoxylate, glycerate and oxaloacetate stimulated oxalate content.
- Taxon
- riceOryza sativat1
- Treatment
- glycolate, glyoxylate, glycerate, and oxaloacetatee0
- Outcome
- oxalate contente0
- Direction
- stimulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“various organic acids, including glycolate, glyoxylate, glycerate, and oxaloacetate, markedly stimulated oxalate content.”
t1“Rice”
Claim · model-written summary
Oxalate levels were positively associated with glycolytic and TCA gene expression.
- Taxon
- riceOryza sativat1
- Gene
- glycolytic and tricarboxylic acid (TCA) cycle genese0
- Outcome
- oxalate levelse0
- Direction
- positively associatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“oxalate levels were closely and positively associated with the expression of glycolytic and tricarboxylic acid (TCA) cycle genes and the content of their intermediate metabolites.”
t1“Rice”
Claim · model-written summary
Oxalate levels were positively associated with glycolytic and TCA intermediate metabolites.
- Taxon
- riceOryza sativat1
- Compound
- intermediate metabolitese0
- Outcome
- oxalate levelse0
- Direction
- positively associatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“oxalate levels were closely and positively associated with the expression of glycolytic and tricarboxylic acid (TCA) cycle genes and the content of their intermediate metabolites.”
t1“Rice”
Claim · model-written summary
Glycolytic intermediates and inhibitors supported a role for glycolysis in oxalate synthesis.
- Taxon
- riceOryza sativae0
- Treatment
- phosphoenolpyruvate (PEP) and 3-phosphoglycerate (3PGA)e0
- Outcome
- oxalate synthesise0
- Qualifier
- glycolysis drivese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment with glycolytic intermediates (phosphoenolpyruvate (PEP) and 3-phosphoglycerate (3PGA)) and inhibitors (iodoacetate (IOA)and 3-bromopyruvate (BrPA)) further confirmed that glycolysis drives oxalate synthesis in rice.”
Claim · model-written summary
Nicotinamide restored oxalate content.
- Taxon
- riceOryza sativat1
- Treatment
- Nicotinamide (NAM)e0
- Outcome
- oxalate contente0
- Direction
- restorede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotinamide (NAM), a NAD precursor, also restored the oxalate content”
t1“Rice”
Claim · model-written summary
Photorespiration was interpreted to affect oxalate indirectly through glycerate-mediated glycolysis.
- Taxon
- riceOryza sativat1
- Compound
- glyceratee0
- Outcome
- oxalate accumulatione0
- Qualifier
- indirectlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“photorespiration, which instead regulates oxalate accumulation indirectly via the glycerate-mediated impact on glycolysis”
t1“Rice”
The same questions in other papers
glycolate · molecular: metabolites · Oryza sativa (rice)Positive and negative results
2 papers in the same direction as this paper · 1 in the opposite direction
- negative
- positive
- positive
glyoxylate · molecular: metabolites · Oryza sativa (rice)Results agree
1 paper in the same direction as this paper
- positive
nitrogen · molecular: metabolites · Oryza sativa (rice)Positive and negative results
34 papers in the same direction as this paper · 86 reporting no difference from an alternative
- positive
- positive
- positive
117 papers more in this group
See all 121 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.