Abstract
In Oncidium, redox homeostasis involved in flowering is mainly due to ascorbic acid (AsA). Here, we discovered that Oncidium floral repression is caused by an increase in AsA-mediated NO levels, which is directed by the enzymatic activities of nitrate reductase (NaR) and nitrite reducatase (NiR). Through Solexa transcriptomic analysis of two libraries, 'pseudobulb with inflorescent bud' (PIB) and 'pseudobulb with axillary bud' (PAB), we identified differentially expressed genes related to NO metabolism. Subsequently, we showed a significant reduction of NaR enzymatic activities and NO levels during bolting and blooming stage, suggesting that NO controlled the phase transition and flowering process. Applying AsA to Oncidium PLB (protocorm-like bodies) significantly elevated the NO content and enzyme activities. Application of sodium nitroprusside (-NO donor) on Arabidopsis vtc1 mutant caused late flowering and expression level of flowering-associated genes (CO, FT and LFY) were reduced, suggesting NO signaling is vital for flowering repression. Conversely, the flowering time of noa1, an Arabidopsis NO-deficient mutant, was not altered after treatment with L-galacturonate, a precursor of AsA, suggesting AsA is required for NO-biosynthesis involved in the NO-mediated flowering-repression pathway. Altogether, Oncidium bolting is tightly regulated by AsA-mediated NO level and downregulation of transcriptional levels of NO metabolism genes.
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Claims 10
Claim · model-written summary
Increased ascorbate-mediated nitric oxide causes Oncidium floral repression.
- Gene
- nitrate reductase (NaR) and nitrite reducatase (NiR)e0
- Compound
- AsA-mediated NOe0
- Outcome
- floral repressione0
OncidiumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Oncidium floral repression is caused by an increase in AsA-mediated NO levels, which is directed by the enzymatic activities of nitrate reductase (NaR) and nitrite reducatase (NiR).”
Claim · model-written summary
Transcriptomics identified genes differentially expressed in nitric oxide metabolism.
- Outcome
- differentially expressed genes related to NO metabolisme0
- Comparator
- 'pseudobulb with axillary bud' (PAB)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Through Solexa transcriptomic analysis of two libraries, 'pseudobulb with inflorescent bud' (PIB) and 'pseudobulb with axillary bud' (PAB), we identified differentially expressed genes related to NO metabolism.”
e1“Oncidium floral repression”
Claim · model-written summary
Nitrate reductase activity fell during bolting and blooming.
- Organ / stage
- bolting and blooming stagee0
- Gene
- NaRe0
- Outcome
- NaR enzymatic activitiese0
- Direction
- reductione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“we showed a significant reduction of NaR enzymatic activities and NO levels during bolting and blooming stage”
e1“Oncidium floral repression”
Claim · model-written summary
Nitric oxide levels fell during bolting and blooming.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“we showed a significant reduction of NaR enzymatic activities and NO levels during bolting and blooming stage”
e1“Oncidium floral repression”
Claim · model-written summary
Ascorbate application increased nitric oxide content in Oncidium PLB.
- Organ / stage
- PLB (protocorm-like bodies)e0
- Treatment
- Applying AsAe0
- Outcome
- NO contente0
- Direction
- elevatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Applying AsA to Oncidium PLB (protocorm-like bodies) significantly elevated the NO content and enzyme activities.”
Claim · model-written summary
Ascorbate application increased enzyme activities in Oncidium PLB.
- Organ / stage
- PLB (protocorm-like bodies)e0
- Treatment
- Applying AsAe0
- Outcome
- enzyme activitiese0
- Direction
- elevatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Applying AsA to Oncidium PLB (protocorm-like bodies) significantly elevated the NO content and enzyme activities.”
Claim · model-written summary
Nitric oxide donor caused late flowering in Arabidopsis vtc1.
- Taxon
- Arabidopsis
Arabidopsise0 - Material
- vtc1 mutante0
- Treatment
- sodium nitroprusside (-NO donor)e0
- Outcome
- floweringe0
- Direction
- latee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Application of sodium nitroprusside (-NO donor) on Arabidopsis vtc1 mutant caused late flowering and expression level of flowering-associated genes (CO, FT and LFY) were reduced”
Claim · model-written summary
Nitric oxide donor reduced flowering-gene expression in Arabidopsis vtc1.
- Taxon
- ArabidopsisArabidopsise0
- Material
- vtc1 mutante0
- Treatment
- sodium nitroprusside (-NO donor)e0
- Gene
- CO, FT and LFYe0
- Outcome
- expression level of flowering-associated genese0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Application of sodium nitroprusside (-NO donor) on Arabidopsis vtc1 mutant caused late flowering and expression level of flowering-associated genes (CO, FT and LFY) were reduced”
Claim · model-written summary
L-galacturonate did not change flowering time in Arabidopsis noa1.
- Taxon
- ArabidopsisArabidopsise0
- Material
- noa1e0
- Treatment
- L-galacturonatee0
- Outcome
- flowering timee0
- Direction
- not alterede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the flowering time of noa1, an Arabidopsis NO-deficient mutant, was not altered after treatment with L-galacturonate, a precursor of AsA”
Claim · model-written summary
Authors infer Oncidium bolting regulation through ascorbate-mediated nitric oxide and NO-metabolism gene downregulation.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Oncidium bolting is tightly regulated by AsA-mediated NO level and downregulation of transcriptional levels of NO metabolism genes.”
The same questions in other papers
nitric oxide donor · molecular: expression · ArabidopsisPositive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- negative
sodium nitroprusside · molecular: expression · ArabidopsisPositive and negative results
3 in the opposite direction
- positive
- positive
- positive
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.