Abstract
Although the mechanisms of nodule N(2) fixation in legumes are now well documented, some uncertainty remains on the metabolic consequences of water deficit. In most cases, little consideration is given to other organs and, therefore, the coordinated changes in metabolism in leaves, roots, and nodules are not well known. Here, the effect of water restriction on exclusively N(2)-fixing alfalfa (Medicago sativa L.) plants was investigated, and proteomic, metabolomic, and physiological analyses were carried out. It is shown that the inhibition of nitrogenase activity caused by water restriction was accompanied by concerted alterations in metabolic pathways in nodules, leaves, and roots. The data suggest that nodule metabolism and metabolic exchange between plant organs nearly reached homeostasis in asparagine synthesis and partitioning, as well as the N demand from leaves. Typically, there was (i) a stimulation of the anaplerotic pathway to sustain the provision of C skeletons for amino acid (e.g. glutamate and proline) synthesis; (ii) re-allocation of glycolytic products to alanine and serine/glycine; and (iii) subtle changes in redox metabolites suggesting the implication of a slight oxidative stress. Furthermore, water restriction caused little change in both photosynthetic efficiency and respiratory cost of N(2) fixation by nodules. In other words, the results suggest that under water stress, nodule metabolism follows a compromise between physiological imperatives (N demand, oxidative stress) and the lower input to sustain catabolism.
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Claims 7
Claim · model-written summary
Water restriction inhibited nitrogenase activity in alfalfa nodules.
- Taxon
- alfalfa
Medicago sativae0 - Organ / stage
- nodulese1
- Treatment
- water restrictione1
- Outcome
- nitrogenase activitye1
- Direction
- inhibitione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Here, the effect of water restriction on exclusively N(2)-fixing alfalfa (Medicago sativa L.) plants was investigated”
e1“It is shown that the inhibition of nitrogenase activity caused by water restriction was accompanied by concerted alterations in metabolic pathways in nodules, leaves, and roots”
Claim · model-written summary
Water restriction was accompanied by concerted alterations in metabolic pathways in nodules, leaves and roots of alfalfa.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- nodules, leaves, and rootse1
- Treatment
- water restrictione1
- Outcome
- metabolic pathwayse1
- Qualifier
- concerted alterationse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Here, the effect of water restriction on exclusively N(2)-fixing alfalfa (Medicago sativa L.) plants was investigated”
e1“It is shown that the inhibition of nitrogenase activity caused by water restriction was accompanied by concerted alterations in metabolic pathways in nodules, leaves, and roots”
Claim · model-written summary
Nodule metabolism and metabolic exchange between organs nearly reached homeostasis in asparagine synthesis and partitioning under water restriction.
- Taxon
- alfalfaMedicago sativae0
- Outcome
- nodule metabolisme4
- Qualifier
- nearly reached homeostasise4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Here, the effect of water restriction on exclusively N(2)-fixing alfalfa (Medicago sativa L.) plants was investigated”
e4“The data suggest that nodule metabolism and metabolic exchange between plant organs nearly reached homeostasis in asparagine synthesis and partitioning, as well as the N demand from leaves”
Claim · model-written summary
Water restriction stimulated the anaplerotic pathway in alfalfa, supplying carbon skeletons for amino acid synthesis.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- water restrictione1
- Outcome
- anaplerotic pathwaye2
- Direction
- stimulatione2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Here, the effect of water restriction on exclusively N(2)-fixing alfalfa (Medicago sativa L.) plants was investigated”
e1“It is shown that the inhibition of nitrogenase activity caused by water restriction was accompanied by concerted alterations in metabolic pathways in nodules, leaves, and roots”
e2“a stimulation of the anaplerotic pathway to sustain the provision of C skeletons for amino acid (e.g. glutamate and proline) synthesis”
Claim · model-written summary
Glycolytic products were re-allocated to alanine and serine/glycine in alfalfa under water restriction.
- Taxon
- alfalfaMedicago sativae0
- Outcome
- re-allocation of glycolytic productse3
- Qualifier
- to alanine and serine/glycinee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Here, the effect of water restriction on exclusively N(2)-fixing alfalfa (Medicago sativa L.) plants was investigated”
e3“re-allocation of glycolytic products to alanine and serine/glycine”
Claim · model-written summary
Subtle changes in redox metabolites suggested a slight oxidative stress under water restriction.
- Taxon
- alfalfaMedicago sativae0
- Outcome
- redox metabolitese6
- Direction
- subtle changese6
- Qualifier
- suggesting the implication of a slight oxidative stresse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Here, the effect of water restriction on exclusively N(2)-fixing alfalfa (Medicago sativa L.) plants was investigated”
e6“subtle changes in redox metabolites suggesting the implication of a slight oxidative stress”
Claim · model-written summary
Water restriction caused little change in photosynthetic efficiency and respiratory cost of N2 fixation by nodules.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- nodulese7
- Treatment
- water restrictione7
- Outcome
- photosynthetic efficiency and respiratory coste7
- Direction
- caused little changee7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Here, the effect of water restriction on exclusively N(2)-fixing alfalfa (Medicago sativa L.) plants was investigated”
e7“water restriction caused little change in both photosynthetic efficiency and respiratory cost of N(2) fixation by nodules”
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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.