scholarly journals Antisense Repression of the Medicago truncatula Nodule-Enhanced Sucrose Synthase Leads to a Handicapped Nitrogen Fixation Mirrored by Specific Alterations in the Symbiotic Transcriptome and Metabolome

2007 ◽  
Vol 145 (4) ◽  
pp. 1600-1618 ◽  
Author(s):  
Markus C. Baier ◽  
Aiko Barsch ◽  
Helge Küster ◽  
Natalija Hohnjec
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Sucrose Synthase ◽  
Antisense Repression

scholarly journals Carbon Metabolism and Bacteroid Functioning Are Involved in the Regulation of Nitrogen Fixation in Medicago truncatula Under Drought and Recovery

2009 ◽  
Vol 22 (12) ◽  
pp. 1565-1576 ◽  
Author(s):  
Estíbaliz Larrainzar ◽  
Stefanie Wienkoop ◽  
Christian Scherling ◽  
Stefan Kempa ◽  
Rubén Ladrera ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Sucrose Synthase ◽  
Metabolic Profile ◽  
Symbiotic Nitrogen Fixation ◽  
Partial Reduction ◽  
N Assimilation ◽  
N Metabolism ◽  
C And N ◽  
C Metabolism

Regulation of symbiotic nitrogen fixation (SNF) during drought stress is complex and not yet fully understood. In the present work, the involvement of nodule C and N metabolism in the regulation of SNF in Medicago truncatula under drought and a subsequent rewatering treatment was analyzed using a combination of metabolomic and proteomic approaches. Drought induced a reduction of SNF rates and major changes in the metabolic profile of nodules, mostly an accumulation of amino acids (Pro, His, and Trp) and carbohydrates (sucrose, galactinol, raffinose, and trehalose). This accumulation was coincidental with a decline in the levels of bacteroid proteins involved in SNF and C metabolism, along with a partial reduction of the levels of plant sucrose synthase 1 (SuSy1). In contrast, the variations in enzymes related to N assimilation were found not to correlate with the reduction in SNF, suggesting that these enzymes do not have a role in the regulation of SNF. Unlike the situation in other legumes such as pea and soybean, the drought-induced inhibition of SNF in M. truncatula appears to be caused by impairment of bacteroid metabolism and N2-fixing capacity rather than a limitation of respiratory substrate.

scholarly journals The Effect of Exogenous Nitrate on LCO Signalling, Cytokinin Accumulation, and Nodule Initiation in Medicago truncatula

Genes ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 988
Author(s):  
Kerstin Gühl ◽  
Rens Holmer ◽  
Ting Ting Xiao ◽  
Defeng Shen ◽  
Titis A. K. Wardhani ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Potent Inhibitor ◽  
Ethylene Biosynthesis ◽  
Wild Type ◽  
Biosynthesis Inhibitor ◽  
Signalling Molecules ◽  
Nodule Initiation

Nitrogen fixation by rhizobia is a highly energy-demanding process. Therefore, nodule initiation in legumes is tightly regulated. Environmental nitrate is a potent inhibitor of nodulation. However, the precise mechanism by which this agent (co)regulates the inhibition of nodulation is not fully understood. Here, we demonstrate that in Medicago truncatula the lipo-chitooligosaccharide-induced accumulation of cytokinins is reduced in response to the application of exogenous nitrate. Under permissive nitrate conditions, perception of rhizobia-secreted signalling molecules leads to an increase in the level of four cytokinins (i.e., iP, iPR, tZ, and tZR). However, under high-nitrate conditions, this increase in cytokinins is reduced. The ethylene-insensitive mutant Mtein2/sickle, as well as wild-type plants grown in the presence of the ethylene biosynthesis inhibitor 2-aminoethoxyvinyl glycine (AVG), is resistant to the inhibition of nodulation by nitrate. This demonstrates that ethylene biosynthesis and perception are required to inhibit nodule organogenesis under high-nitrate conditions.

Differential responses of the sunn4 and rdn1-1 super-nodulation mutants of Medicago truncatula to elevated atmospheric CO2

2021 ◽  
Author(s):  
Yunfa Qiao ◽  
Shujie Miao ◽  
Jian Jin ◽  
Ulrike Mathesius ◽  
Caixian Tang
Keyword(s):  
Nitrogen Fixation ◽  
Elevated Co2 ◽  
Medicago Truncatula ◽  
N2 Fixation ◽  
Sink Strength ◽  
Wild Type ◽  
Total N ◽  
Autoregulation Of Nodulation ◽  
Nodulation Mutants ◽  
Fixation Capacity

Abstract Background and Aims Nitrogen fixation in legumes requires tight control of carbon and nitrogen balance. Thus, legumes control nodule numbers via an autoregulation mechanism. ‘Autoregulation of nodulation’ mutants super-nodulate and are thought to be carbon-limited due to the high carbon-sink strength of excessive nodules. This study aimed to examine the effect of increasing carbon supply on the performance of super-nodulation mutants. Methods We compared the responses of Medicago truncatula super-nodulation mutants (sunn-4 and rdn1-1) and wild type to five CO2 levels (300-850 μmol mol -1). Nodule formation and N2 fixation were assessed in soil-grown plants at 18 and 42 days after sowing. Key results Shoot and root biomass, nodule number and biomass, nitrogenase activity and fixed-N per plant of all genotypes increased with increasing CO2 concentration and reached the maximum around 700 μmol mol -1. While the sunn-4 mutant showed strong growth-retardation compared to wild-type plants, elevated CO2 increased shoot biomass and total N content of rdn1-1 mutant up to two-fold. This was accompanied by a four-fold increase in nitrogen fixation capacity in the rdn1-1 mutant. Conclusions These results suggest that the super-nodulation phenotype per se did not limit growth. The additional nitrogen fixation capacity of the rdn1-1 mutant may enhance the benefit of elevated CO2 on plant growth and N2 fixation.

scholarly journals Sucrose Synthase in Legume Nodules Is Essential for Nitrogen Fixation

1999 ◽  
Vol 120 (3) ◽  
pp. 867-878 ◽  
Author(s):  
Anthony J. Gordon ◽  
Frank R. Minchin ◽  
Caron L. James ◽  
Olga Komina
Keyword(s):  
Nitrogen Fixation ◽  
Sucrose Synthase

Phoma medicaginis colonizes Medicago truncatula root nodules and affects nitrogen fixation capacity

2014 ◽  
Vol 141 (2) ◽  
pp. 375-383 ◽  
Author(s):  
Saif-Allah Chihaoui ◽  
Naceur Djébali ◽  
Moncef Mrabet ◽  
Fathi Barhoumi ◽  
Ridha Mhamdi ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Root Nodules ◽  
Phoma Medicaginis ◽  
Fixation Capacity

scholarly journals Nicotianamine Synthase 2 Is Required for Symbiotic Nitrogen Fixation in Medicago truncatula Nodules

2020 ◽  
Vol 10 ◽  
Author(s):  
Viviana Escudero ◽  
Isidro Abreu ◽  
Eric del Sastre ◽  
Manuel Tejada-Jiménez ◽  
Camille Larue ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Symbiotic Nitrogen Fixation ◽  
Nicotianamine Synthase

scholarly journals Medicago truncatula Phytoglobin 1.1 controls symbiotic nodulation and nitrogen fixation via the regulation of nitric oxide concentration

2020 ◽  
Vol 227 (1) ◽  
pp. 84-98 ◽  
Author(s):  
Antoine Berger ◽  
Sophie Guinand ◽  
Alexandre Boscari ◽  
Alain Puppo ◽  
Renaud Brouquisse
Keyword(s):  
Nitric Oxide ◽  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Oxide Concentration ◽  
Nitric Oxide Concentration
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