Abstract
The osmoprotectant Pro betaine is the main betaine identified in alfalfa (Medicago sativa). We have investigated the long-term responses of nodulated alfalfa plants to salt stress, with a particular interest for Pro betaine accumulation, compartmentalization, and metabolism. Exposure of 3-week-old nodulated alfalfa plants to 0.2 m NaCl for 4 weeks was followed by a 10-, 4-, and 8-fold increase in Pro betaine in shoots, roots, and nodules, respectively. Isotope-labeling studies in alfalfa shoots indicate that [14C]Pro betaine was synthesized from l-[14C]Pro. [14C]Pro betaine was efficiently catabolized through sequential demethylations via N-methylPro and Pro. Salt stress had a minor effect on Pro betaine biosynthesis, whereas it strongly reduced Pro betaine turnover. Analysis of Pro betaine and Pro compartmentalization within nodules revealed that 4 weeks of salinization of the host plants induced a strong increase in cytosol and bacteroids. The estimated Pro betaine and Pro concentrations in salt-stressed bacteroids reached 7.4 and 11.8 mm, respectively, compared to only 0.8 mm in control bacteroids. Na+ content in nodule compartments was also enhanced under salinization, leading to a concentration of 14.7 mm in bacteroids. [14C]Pro betaine and [14C]Pro were taken up by purified symbiosomes and free bacteroids. There was no indication of saturable carrier(s), and the rate of uptake was moderately enhanced by salinization. Ultrastructural analysis showed a large peribacteroid space in salt-stressed nodules, suggesting an increased turgor pressure inside the symbiosomes, which might partially be due to an elevated concentration in Pro, Pro betaine, and Na+ in this compartment.
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Claims 11
Claim · model-written summary
Salt stress increased Pro betaine in shoots, roots and nodules by 10-, 4- and 8-fold.
- Taxon
- alfalfa
Medicago sativae0 - Organ / stage
- shoots, roots, and nodulese1
- Treatment
- 0.2 m NaCle1
- Outcome
- Pro betainee1
- Direction
- increasee1
- Value
- 10-, 4-, and 8-folde1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The osmoprotectant Pro betaine is the main betaine identified in alfalfa (Medicago sativa)”
e1“Exposure of 3-week-old nodulated alfalfa plants to 0.2 m NaCl for 4 weeks was followed by a 10-, 4-, and 8-fold increase in Pro betaine in shoots, roots, and nodules, respectively”
Claim · model-written summary
[14C]Pro betaine was synthesized from l-[14C]Pro in alfalfa shoots.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- shootse2
- Compound
- Pro betainee2
- Outcome
- synthesizede2
- Qualifier
- from l-[14C]Proe2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The osmoprotectant Pro betaine is the main betaine identified in alfalfa (Medicago sativa)”
e2“Isotope-labeling studies in alfalfa shoots indicate that [14C]Pro betaine was synthesized from l-[14C]Pro”
Claim · model-written summary
Pro betaine was efficiently catabolized in alfalfa through sequential demethylations via N-methylPro and Pro.
- Taxon
- alfalfaMedicago sativae0
- Compound
- Pro betainee3
- Outcome
- catabolizede3
- Qualifier
- through sequential demethylations via N-methylPro and Proe3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The osmoprotectant Pro betaine is the main betaine identified in alfalfa (Medicago sativa)”
e3“[14C]Pro betaine was efficiently catabolized through sequential demethylations via N-methylPro and Pro”
Claim · model-written summary
Salt stress had a minor effect on Pro betaine biosynthesis in alfalfa.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- Salt stresse4
- Outcome
- Pro betaine biosynthesise4
- Direction
- no_changeinferrede4
- Qualifier
- minor effecte4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The osmoprotectant Pro betaine is the main betaine identified in alfalfa (Medicago sativa)”
e4“Salt stress had a minor effect on Pro betaine biosynthesis, whereas it strongly reduced Pro betaine turnover”
Claim · model-written summary
Salt stress strongly reduced Pro betaine turnover in alfalfa.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- Salt stresse4
- Outcome
- Pro betaine turnovere4
- Direction
- reducede4
- Qualifier
- stronglye4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The osmoprotectant Pro betaine is the main betaine identified in alfalfa (Medicago sativa)”
e4“Salt stress had a minor effect on Pro betaine biosynthesis, whereas it strongly reduced Pro betaine turnover”
Claim · model-written summary
In salt-stressed bacteroids, Pro betaine and Pro concentrations reached 7.4 and 11.8 mm, compared with 0.8 mm for Pro betaine in control bacteroids.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- salt-stressed bacteroidse5
- Compound
- Pro betainee5
- Outcome
- Pro betaine and Pro concentrationse5
- Value
- 7.4 and 11.8 mme5
- Qualifier
- compared to only 0.8 mm in control bacteroidse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The osmoprotectant Pro betaine is the main betaine identified in alfalfa (Medicago sativa)”
e5“The estimated Pro betaine and Pro concentrations in salt-stressed bacteroids reached 7.4 and 11.8 mm, respectively, compared to only 0.8 mm in control bacteroids”
Claim · model-written summary
Salinization enhanced Na+ content in nodule compartments, reaching 14.7 mm in bacteroids.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- nodule compartmentse6
- Treatment
- salinizatione6
- Outcome
- Na+ contente6
- Direction
- enhancede6
- Value
- 14.7 mme6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The osmoprotectant Pro betaine is the main betaine identified in alfalfa (Medicago sativa)”
e6“Na+ content in nodule compartments was also enhanced under salinization, leading to a concentration of 14.7 mm in bacteroids”
Claim · model-written summary
Salinization moderately enhanced the rate of uptake of Pro betaine and Pro by alfalfa symbiosomes and bacteroids.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- salinizatione7
- Outcome
- rate of uptakee7
- Direction
- enhancede7
- Qualifier
- moderatelye7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The osmoprotectant Pro betaine is the main betaine identified in alfalfa (Medicago sativa)”
e7“the rate of uptake was moderately enhanced by salinization”
Claim · model-written summary
Pro betaine was taken up by purified symbiosomes and free bacteroids of alfalfa.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- purified symbiosomes and free bacteroidse1
- Compound
- Pro betainee1
- Outcome
- taken upe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The osmoprotectant Pro betaine is the main betaine identified in alfalfa (Medicago sativa)”
e1“[14C]Pro betaine and [14C]Pro were taken up by purified symbiosomes and free bacteroids”
Claim · model-written summary
Salt-stressed alfalfa nodules showed a large peribacteroid space.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- salt-stressed nodulese1
- Outcome
- peribacteroid spacee1
- Qualifier
- largee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The osmoprotectant Pro betaine is the main betaine identified in alfalfa (Medicago sativa)”
e1“Ultrastructural analysis showed a large peribacteroid space in salt-stressed nodules”
Claim · model-written summary
No indication of saturable carrier(s) was found for uptake of Pro betaine and Pro by alfalfa symbiosomes.
- Taxon
- alfalfaMedicago sativae0
- Outcome
- saturable carrier(s)e1
- Qualifier
- no indicatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The osmoprotectant Pro betaine is the main betaine identified in alfalfa (Medicago sativa)”
e1“There was no indication of saturable carrier(s)”
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See all 10 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.