Abstract
Choline metabolism was examined in spinach (Spinacia oleracea L.) plants growing under nonsaline and saline conditions. In spinach, choline is required for phosphatidylcholine synthesis and as a precursor for the compatible osmolyte glycine betaine (betaine). When control (nonsalinized) leaf discs were incubated for up to 2 h with [1,2-14C]ethanolamine, label appeared in the N-methylated derivatives of phosphoethanolamine including phosphomono-, phosphodi-, and phosphotri- (i.e. phosphocholine) methyl-ethanolamine, as well as in choline and betaine, whereas no radioactivity could be detected in the mono- and dimethylated derivatives of the free base ethanolamine. Leaf discs from salinized plants showed the same pattern of labeling, although the proportion of label that accumulated in betaine was almost 3-fold higher in the salinized leaf discs. Enzymes involved in choline metabolism were assayed in crude leaf extracts of plants. The activites of ethanolamine kinase and of the three S-adenosylmethionine:phospho-base N-methyltransferase enzymes responsible for N-methylating phosphoethanolamine to phosphocholine were all higher in extracts of plants salinized step-wise to 100, 200, or 300 mM NaCI compared with controls. In contrast, choline kinase, phosphocholine phosphatase, and cytidine 5[prime]-triphosphate: phosphocholine cytidylyltransferase activities showed little variation with salt stress. Thus, the increased diversion of choline to betaine in salt-stressed spinach appears to be mediated by the increased activity of several key enzymes involved in choline biosynthesis.
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Claims 8
Claim · model-written summary
Control spinach leaf discs incorporated ethanolamine label into phosphoethanolamine derivatives, choline and betaine.
- Taxon
- Spinach
Spinacia oleraceat0 - Organ / stage
- leaf discse0
- Outcome
- label appeared in the N-methylated derivatives of phosphoethanolaminee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When control (nonsalinized) leaf discs were incubated for up to 2 h with [1,2-14C]ethanolamine, label appeared in the N-methylated derivatives of phosphoethanolamine including phosphomono-, phosphodi-, and phosphotri- (i.e. phosphocholine) methyl-ethanolamine, as well as in choline and betaine”
t0“Spinach”
Claim · model-written summary
No label was detected in mono- or dimethylated free ethanolamine derivatives.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- no radioactivity could be detected in the mono- and dimethylated derivatives of the free base ethanolaminee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no radioactivity could be detected in the mono- and dimethylated derivatives of the free base ethanolamine”
t0“Spinach”
Claim · model-written summary
Salinized leaf discs showed the same labeling pattern as controls.
- Taxon
- SpinachSpinacia oleraceat0
- Organ / stage
- Leaf discse0
- Outcome
- same pattern of labelinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf discs from salinized plants showed the same pattern of labeling”
t0“Spinach”
Claim · model-written summary
Betaine label proportion was almost threefold higher in salinized leaf discs.
- Taxon
- SpinachSpinacia oleraceat0
- Treatment
- salinizede0
- Outcome
- proportion of label that accumulated in betainee0
- Direction
- highere0
- Value
- almost 3-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the proportion of label that accumulated in betaine was almost 3-fold higher in the salinized leaf discs”
t0“Spinach”
Claim · model-written summary
Ethanolamine kinase activity was higher after salinization.
- Taxon
- SpinachSpinacia oleraceat0
- Treatment
- salinized step-wise to 100, 200, or 300 mM NaCIe0
- Gene
- ethanolamine kinasee0
- Outcome
- activites of ethanolamine kinasee0
- Direction
- highere0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The activites of ethanolamine kinase and of the three S-adenosylmethionine:phospho-base N-methyltransferase enzymes responsible for N-methylating phosphoethanolamine to phosphocholine were all higher in extracts of plants salinized step-wise to 100, 200, or 300 mM NaCI compared with controls”
t0“Spinach”
Claim · model-written summary
Three phospho-base N-methyltransferase enzyme activities were higher after salinization.
- Taxon
- SpinachSpinacia oleraceat0
- Treatment
- salinized step-wise to 100, 200, or 300 mM NaCIe0
- Gene
- S-adenosylmethionine:phospho-base N-methyltransferasee0
- Outcome
- three S-adenosylmethionine:phospho-base N-methyltransferase enzymese0
- Direction
- highere0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The activites of ethanolamine kinase and of the three S-adenosylmethionine:phospho-base N-methyltransferase enzymes responsible for N-methylating phosphoethanolamine to phosphocholine were all higher in extracts of plants salinized step-wise to 100, 200, or 300 mM NaCI compared with controls”
t0“Spinach”
Claim · model-written summary
Choline kinase, phosphocholine phosphatase and cytidylyltransferase activities varied little with salt stress.
- Taxon
- SpinachSpinacia oleraceat0
- Treatment
- salt stresse0
- Outcome
- choline kinase, phosphocholine phosphatase, and cytidine 5[prime]-triphosphate: phosphocholine cytidylyltransferase activitiese0
- Direction
- little variatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“choline kinase, phosphocholine phosphatase, and cytidine 5[prime]-triphosphate: phosphocholine cytidylyltransferase activities showed little variation with salt stress”
t0“Spinach”
Claim · model-written summary
Authors inferred that higher biosynthetic enzyme activity mediates choline diversion to betaine under salt stress.
- Taxon
- spinachSpinacia oleraceae0
- Outcome
- increased diversion of choline to betainee0
- Qualifier
- increased activity of several key enzymes involved in choline biosynthesise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increased diversion of choline to betaine in salt-stressed spinach appears to be mediated by the increased activity of several key enzymes involved in choline biosynthesis”
The same questions in other papers
salinity · physiology: enzyme activity · Spinacia oleracea (spinach)Positive and negative results
1 in the opposite direction
- negative
salinity · molecular: metabolites · Spinacia oleracea (spinach)Positive and negative results
3 papers in the same direction as this paper · 4 in the opposite direction
- positive
- no effect
- no effect
4 papers more in this group
See all 8 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.