Abstract
In this study, we addressed the effects of N limitation in Bradyrhizobium japonicum for its association with soybean roots. The wild-type strain LP 3001 grew for six generations with a growth rate of 1.2 day(-1) in a minimal medium with 28 mM mannitol as the carbon source and with the N source [(NH(4))(2)SO(4)] limited to only 20 microM. Under these conditions, the glutamine synthetase (GS) activity was five to six times higher than in similar cultures grown with 1 or 0.1 mM (NH(4))(2)SO(4). The NtrBC-inducible GSII form of this enzyme accounted for 60% of the specific activity in N-starved rhizobia, being negligible in the other two cultures. The exopolysaccharide (EPS) and capsular polysaccharide (CPS) contents relative to cell protein were significantly higher in the N-starved cultures, but on the other hand, the poly-3-hydroxybutyrate level did not rise in comparison with N-sufficient cultures. In agreement with the accumulation of CPS in N-starved cultures, soybean lectin (SBL) binding as well as stimulation of rhizobial adsorption to soybean roots by SBL pretreatment were higher. The last effect was evident only in cultures that had not entered stationary phase. We also studied nodC gene induction in relation to N starvation. In the chromosomal nodC::lacZ fusion Bj110-573, nodC gene expression was induced by genistein 2.7-fold more in N-starved young cultures than in nonstarved ones. In stationary-phase cultures, nodC gene expression was similarly induced in N-limited cultures, but induction was negligible in cultures limited by another nutrient. Nodulation profiles obtained with strain LP 3001 grown under N starvation indicated that these cultures nodulated faster. In addition, as culture age increased, the nodulation efficiency decreased for two reasons: fewer nodules were formed, and nodulation was delayed. However, their relative importance was different according to the nutrient condition: in older cultures the overall decrease in the number of nodules was the main effect in N-starved cultures, whereas a delay in nodulation was more responsible for a loss in efficiency of N-sufficient cultures. Competition for nodulation was studied with young cultures of two wild-type strains differing only in their antibiotic resistance, the N-starved cultures being the most competitive.
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Claims 16
Claim · model-written summary
Nitrogen-starved rhizobia grew for six generations at 1.2 day(-1).
- Taxon
- Soybean
Glycine maxt0 - Treatment
- 20 microMe0
- Interactor
- Bradyrhizobium japonicum
Bradyrhizobium japonicumt0symbiont - Outcome
- growth ratee0
- Value
- 1.2 day(-1)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The wild-type strain LP 3001 grew for six generations with a growth rate of 1.2 day(-1) in a minimal medium with 28 mM mannitol as the carbon source and with the N source [(NH(4))(2)SO(4)] limited to only 20 microM.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
Nitrogen starvation raised rhizobial glutamine synthetase activity five to sixfold.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- N-Starvedt0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Gene
- glutamine synthetase (GS)e0
- Outcome
- glutamine synthetase (GS) activitye0
- Direction
- highere0
- Value
- five to six timese0
- Comparator
- 1 or 0.1 mM (NH(4))(2)SO(4)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under these conditions, the glutamine synthetase (GS) activity was five to six times higher than in similar cultures grown with 1 or 0.1 mM (NH(4))(2)SO(4).”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
GSII accounted for 60% of enzyme activity in nitrogen-starved rhizobia and was negligible in other cultures.
- Taxon
- SoybeanGlycine maxt0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Gene
- GSIIe0
- Outcome
- specific activitye0
- Value
- 60%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The NtrBC-inducible GSII form of this enzyme accounted for 60% of the specific activity in N-starved rhizobia, being negligible in the other two cultures.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
Nitrogen starvation increased rhizobial exopolysaccharide content.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- N-starved culturese0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Outcome
- exopolysaccharide (EPS)e0
- Direction
- highere0
- Comparator
- N-sufficient culturese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The exopolysaccharide (EPS) and capsular polysaccharide (CPS) contents relative to cell protein were significantly higher in the N-starved cultures, but on the other hand, the poly-3-hydroxybutyrate level did not rise in comparison with N-sufficient cultures.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
Nitrogen starvation increased rhizobial capsular polysaccharide content.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- N-starved culturese0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Outcome
- capsular polysaccharide (CPS) contentse0
- Direction
- highere0
- Comparator
- N-sufficient culturese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The exopolysaccharide (EPS) and capsular polysaccharide (CPS) contents relative to cell protein were significantly higher in the N-starved cultures, but on the other hand, the poly-3-hydroxybutyrate level did not rise in comparison with N-sufficient cultures.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
Poly-3-hydroxybutyrate did not rise under nitrogen starvation.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- N-starved culturese1
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Outcome
- poly-3-hydroxybutyrate levele0
- Direction
- did not risee0
- Comparator
- N-sufficient culturese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the poly-3-hydroxybutyrate level did not rise in comparison with N-sufficient cultures.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
e1“The exopolysaccharide (EPS) and capsular polysaccharide (CPS) contents relative to cell protein were significantly higher in the N-starved cultures, but on the other hand, the poly-3-hydroxybutyrate level did not rise in comparison with N-sufficient cultures.”
Claim · model-written summary
Soybean lectin binding was higher in nitrogen-starved cultures.
- Taxon
- SoybeanGlycine maxe0
- Treatment
- N-starved culturese1
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Outcome
- soybean lectin (SBL) bindinge0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean lectin (SBL) binding as well as stimulation of rhizobial adsorption to soybean roots by SBL pretreatment were higher.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
e1“The exopolysaccharide (EPS) and capsular polysaccharide (CPS) contents relative to cell protein were significantly higher in the N-starved cultures, but on the other hand, the poly-3-hydroxybutyrate level did not rise in comparison with N-sufficient cultures.”
Claim · model-written summary
SBL pretreatment stimulated rhizobial adsorption to soybean roots more in nitrogen-starved young cultures.
- Taxon
- SoybeanGlycine maxe0
- Treatment
- SBL pretreatmente0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Outcome
- rhizobial adsorption to soybean rootse0
- Direction
- highere0
- Qualifier
- cultures that had not entered stationary phasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“stimulation of rhizobial adsorption to soybean roots by SBL pretreatment were higher. The last effect was evident only in cultures that had not entered stationary phase.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
Genistein induced nodC expression 2.7-fold more in nitrogen-starved young cultures.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- genisteine0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Gene
- nodCe0
- Outcome
- nodC gene expressione0
- Direction
- moree0
- Value
- 2.7-folde0
- Comparator
- nonstarved onese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the chromosomal nodC::lacZ fusion Bj110-573, nodC gene expression was induced by genistein 2.7-fold more in N-starved young cultures than in nonstarved ones.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
In stationary phase, nodC induction persisted under nitrogen limitation but was negligible under other nutrient limitation.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- N-limited culturese0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Gene
- nodCe0
- Outcome
- nodC gene expressione0
- Direction
- similarly inducede0
- Comparator
- cultures limited by another nutriente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In stationary-phase cultures, nodC gene expression was similarly induced in N-limited cultures, but induction was negligible in cultures limited by another nutrient.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
Nitrogen-starved cultures nodulated soybean faster.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- N starvatione0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Outcome
- Nodulatione0
- Direction
- fastere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nodulation profiles obtained with strain LP 3001 grown under N starvation indicated that these cultures nodulated faster.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
Older cultures formed fewer nodules.
- Taxon
- SoybeanGlycine maxt0
- Organ / stage
- culture agee0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Outcome
- nodulese0
- Direction
- fewere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“as culture age increased, the nodulation efficiency decreased for two reasons: fewer nodules were formed, and nodulation was delayed.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
Older cultures had delayed nodulation.
- Taxon
- SoybeanGlycine maxt0
- Organ / stage
- culture agee0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Outcome
- nodulatione0
- Direction
- delayede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“as culture age increased, the nodulation efficiency decreased for two reasons: fewer nodules were formed, and nodulation was delayed.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
With age, fewer nodules chiefly reduced efficiency of nitrogen-starved cultures.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- N-starved culturese0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Outcome
- number of nodulese0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in older cultures the overall decrease in the number of nodules was the main effect in N-starved cultures”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
With age, nodulation delay chiefly reduced efficiency of nitrogen-sufficient cultures.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- N-sufficient culturese0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Outcome
- nodulatione0
- Direction
- delaye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a delay in nodulation was more responsible for a loss in efficiency of N-sufficient cultures.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
Claim · model-written summary
Nitrogen-starved young cultures were most competitive for nodulation.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- N-starved culturese0
- Interactor
- Bradyrhizobium japonicumBradyrhizobium japonicumt0symbiont
- Outcome
- competitivee0
- Direction
- most competitivee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Competition for nodulation was studied with young cultures of two wild-type strains differing only in their antibiotic resistance, the N-starved cultures being the most competitive.”
t0“Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum”
The same questions in other papers
nitrogen · Bradyrhizobium japonicum · Glycine max (soybean)Positive and negative results
5 papers in the same direction as this paper · 5 in the opposite direction
This paper is about lacking the nutrient, so it counts the other way round here.
- positive
- positive
- positive
7 papers more in this group
See all 11 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.