scholarly journals ANALYSIS OF MEMBRANE TRANSPORTER SYSTEMS EXPRESSED DURING SYMBIOTIC NITROGEN FIXATION IN THE MODEL LEGUME MEDICAGO TRUNCATULA

2018 ◽  
Author(s):  
Christina Laureen Wyman
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Symbiotic Nitrogen Fixation ◽  
Membrane Transporter ◽  
Model Legume ◽  
Transporter Systems

scholarly journals Nicotianamine synthase 2 is required for symbiotic nitrogen fixation in Medicago truncatula nodules

2019 ◽  
Author(s):  
Viviana Escudero ◽  
Isidro Abreu ◽  
Eric del Sastre ◽  
Manuel Tejada-Jiménez ◽  
Camile Larue ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Symbiotic Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Long Distance ◽  
Metal Transporters ◽  
Model Legume ◽  
Fluorescence Studies ◽  
Iron Delivery

SUMMARYSymbiotic nitrogen fixation carried out by the interaction between legumes and diazotrophic bacteria known as rhizobia requires of relatively large levels of transition metals. These elements act as cofactors of many key enzymes involved in this process. Metallic micronutrients are obtained from soil by the roots and directed to sink organs by the vasculature, in a process participated by a number of metal transporters and small organic molecules that mediate metal delivery in the plant fluids. Among the later, nicotianamine is one of the most important. Synthesized by nicotianamine synthases (NAS), this non-proteinogenic amino acid forms metal complexes participating in intracellular metal homeostasis and long-distance metal trafficking. Here we characterized the NAS2 gene from model legume Medicago truncatula. MtNAS2 is located in the root vasculature and in all nodule tissues in the infection and fixation zones. Symbiotic nitrogen fixation requires of MtNAS2 function, as indicated by the loss of nitrogenase activity in the insertional mutant nas2-1, a phenotype reverted by reintroduction of a wild-type copy of MtNAS2. This would be the result of the altered iron distribution in nas2-1 nodules, as indicated by X-ray fluorescence studies. Moreover, iron speciation is also affected in these nodules. These data suggest a role of nicotianamine in iron delivery for symbiotic nitrogen fixation.Significance StatementNicotianamine synthesis mediated by MtNAS2 is important for iron allocation for symbiotic nitrogen fixation by rhizobia in Medicago truncatula root nodules.

scholarly journals Medicago truncatulacopper transporter 1 (MtCOPT1) delivers copper for symbiotic nitrogen fixation

2017 ◽  
Author(s):  
Marta Senovilla ◽  
Rosario Castro-Rodríguez ◽  
Isidro Abreu ◽  
Viviana Escudero ◽  
Igor Kryvoruchko ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Symbiotic Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Yeast Complementation ◽  
Copper Transporter ◽  
Model Legume ◽  
Essential Nutrient ◽  
Early Fixation

Summary• Copper is an essential nutrient for symbiotic nitrogen fixation. This element is delivered by the host plant to the nodule, where membrane copper transporter would introduce it into the cell to synthesize cupro-proteins.• COPT family members in model legumeMedicago truncatulawere identified and their expression determined. Yeast complementation assays, confocal microscopy, and phenotypical characterization of aTnt1insertional mutant line were carried out in the nodule-specificM.truncatulaCOPT family member.•Medicago truncatulagenome encodes eight COPT transporters.MtCOPT1(Medtr4g019870) is the only nodule-specificCOPTgene. It is located in the plasma membrane of the differentiation, interzone and early fixation zones. Loss of MtCOPT1 function results in a copper-mitigated reduction of biomass production when the plant obtains its nitrogen exclusively from symbiotic nitrogen fixation. Mutation ofMtCOPT1results in diminished nitrogenase activity in nodules, likely an indirect effect from the loss of a copper-dependent function, such as cytochrome oxidase activity incopt1-1bacteroids.• These data are consistent with a model in which MtCOPT1 transports copper from the apoplast into nodule cells to provide copper for essential metabolic processes associated with symbiotic nitrogen fixation.

scholarly journals The Medicago truncatula Yellow Stripe1-Like3 gene is involved in vascular delivery of transition metals to root nodules

2020 ◽  
Vol 71 (22) ◽  
pp. 7257-7269
Author(s):  
Rosario Castro-Rodríguez ◽  
Isidro Abreu ◽  
María Reguera ◽  
Lorena Novoa-Aponte ◽  
Ana Mijovilovich ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Transition Metals ◽  
Medicago Truncatula ◽  
Symbiotic Nitrogen Fixation ◽  
Root Nodules ◽  
Apical Region ◽  
Long Distance ◽  
Metal Transporters ◽  
Model Legume ◽  
Iron And Zinc

Abstract Symbiotic nitrogen fixation carried out in legume root nodules requires transition metals. These nutrients are delivered by the host plant to the endosymbiotic nitrogen-fixing bacteria living within the nodule cells, a process in which vascular transport is essential. As members of the Yellow Stripe-Like (YSL) family of metal transporters are involved in root to shoot transport, they should also be required for root to nodule metal delivery. The genome of the model legume Medicago truncatula encodes eight YSL proteins, four of them with a high degree of similarity to Arabidopsis thaliana YSLs involved in long-distance metal trafficking. Among them, MtYSL3 is a plasma membrane protein expressed by vascular cells in roots and nodules and by cortical nodule cells. Reducing the expression level of this gene had no major effect on plant physiology when assimilable nitrogen was provided in the nutrient solution. However, nodule functioning was severely impaired, with a significant reduction of nitrogen fixation capabilities. Further, iron and zinc accumulation and distribution changed. Iron was retained in the apical region of the nodule, while zinc became strongly accumulated in the nodule veins in the ysl3 mutant. These data suggest a role for MtYSL3 in vascular delivery of iron and zinc to symbiotic nitrogen fixation.

scholarly journals Medicago truncatula Yellow Stripe1-Like3 gene is involved in symbiotic nitrogen fixation

2019 ◽  
Author(s):  
Rosario Castro-Rodríguez ◽  
Isidro Abreu ◽  
María Reguera ◽  
Lorena Novoa-Aponte ◽  
Ana Mijovilovich ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Symbiotic Nitrogen Fixation ◽  
Root Nodules ◽  
Major Effect ◽  
Apical Region ◽  
Long Distance ◽  
Metal Transporters ◽  
Model Legume ◽  
Iron And Zinc

AbstractSymbiotic nitrogen fixation carried out in legume root nodules requires transition metals. These nutrients are delivered by the host plant to the endosymbiotic nitrogen-fixing bacteria living with the nodule cells, a process in which vascular transport is essential. As occurs in root-to-shoot transport, members of the Yellow Stripe-Like (YSL) family of metal transporters should also be required for root-to-nodule metal delivery. The genome of the model legume Medicago truncatula encodes for eight YSL proteins, four of them with a high degree of similarity to Arabidopsis thaliana YSLs involved in long-distance metal trafficking. Among them, MtYSL3 is a plasma membrane protein expressed by vascular cells in roots and nodules, and by cortical nodule cells. Reducing expression levels of this gene had no major effect on plant physiology when assimilable nitrogen was provided in the nutrient solution. However, nodule functioning was severely impaired, with a significant reduction of nitrogen fixation capabilities. Further, iron and zinc accumulation and distribution changed. Iron was retained in the apical region of the nodule, while zinc became strongly accumulated in the nodule veins in the ysl3 mutant. These data suggest a role of MtYSL3 in vascular delivery of iron and zinc to symbiotic nitrogen fixation.HighlightMedicago truncatula YSL3 transporter is required for optimal nitrogen fixation in root nodules, mediating iron and zinc distribution in these organs.

scholarly journals Αναπρογραμματισμός του μεταβολισμού του Lotus japonicus σε μεταγραφικό, βιοχημικό και μεταβολομικό επίπεδο κατά τη συμβιωτική αζωτοδέσμευση

2016 ◽  
Author(s):  
Χρυσάνθη Καλλονιάτη
Keyword(s):  
Nitrogen Fixation ◽  
Metabolite Profiling ◽  
Symbiotic Nitrogen Fixation ◽  
Sulfur Metabolism ◽  
Lotus Japonicus ◽  
Nitrogen Fixing ◽  
Model Legume ◽  
Whole Plant ◽  
Plant Level ◽  
Molecular And Biochemical Mechanisms

Symbiotic nitrogen fixation in legumes takes place in specialized organs called nodules,which become the main source of assimilated nitrogen for the whole plant. Symbiotic nitro‐gen fixation requires exquisite integration of plant and bacterial metabolism and involvesglobal changes in gene expression and metabolite accumulation in both rhizobia and thehost plant. In order to study the metabolic changes mediated by symbiotic nitrogen fixationon a whole‐plant level, metabolite levels were profiled by gas chromatography–mass spec‐trometry in nodules and non‐symbiotic organs of Lotus japonicus plants uninoculated or in‐oculated with M. loti wt,  ΔnifA or  ΔnifH fix‐ strains. Furthermore, transcriptomic andbiochemical approaches were combined to study sulfur metabolism in nodules, its link tosymbiotic nitrogen fixation, and the effect of nodules on whole‐plant sulfur partitioning andmetabolism. It is well established that nitrogen and sulfur (S) metabolism are tightly en‐twined and sulfur is required for symbiotic nitrogen fixation, however, little is known aboutthe molecular and biochemical mechanisms governing sulfur uptake and assimilation duringsymbiotic nitrogen fixation. Transcript profiling in Lotus japonicus was combined with quan‐tification of S‐metabolite contents and APR activity in nodules and in non‐symbiotic organsof plants uninoculated or inoculated with M. loti wt, ΔnifA or ΔnifH fix‐ strains. Moreover,sulfate uptake and its distribution into different plant organs were analyzed and 35S‐flux intodifferent S‐pools was monitored. Metabolite profiling revealed that symbiotic nitrogen fixa‐tion results in dramatic changes of many aspects of primary and secondary metabolism innodules which leads to global reprogramming of metabolism of the model legume on awhole‐plant level. Moreover, our data revealed that nitrogen fixing nodules represent athiol‐rich organ. Their high APR activity and 35S‐flux into cysteine and its metabolites in com‐bination with the transcriptional up‐regulation of several genes involved in sulfur assimila‐tion highlight the function of nodules as a new site of sulfur assimilation. The higher thiolcontent observed in non‐symbiotic organs of nitrogen fixing plants in comparison touninoculated plants cannot be attributed to local biosynthesis, indicating that nodules couldserve as a novel source of reduced sulfur for the plant, which triggers whole‐plant repro‐gramming of sulfur metabolism. Interestingly, the changes in metabolite profiling and theenhanced thiol biosynthesis in nodules and their impact on the whole‐plant sulfur, carbonand nitrogen economy are dampened in fix‐ plants, which in most respects metabolically re‐sembled uninoculated plants, indicating a strong interaction between nitrogen fixation andsulfur and carbon metabolism.

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 Aphid infestation differently affects the defences of nitrate-fed and nitrogen-fixing Medicago truncatula and alters symbiotic nitrogen fixation

2020 ◽  
Vol 287 (1934) ◽  
pp. 20201493
Author(s):  
Gaurav Pandharikar ◽  
Jean-Luc Gatti ◽  
Jean-Christophe Simon ◽  
Pierre Frendo ◽  
Marylène Poirié
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Acyrthosiphon Pisum ◽  
Symbiotic Nitrogen Fixation ◽  
Pea Aphid ◽  
Systemic Resistance ◽  
Aphid Infestation ◽  
Plant Nitrogen ◽  
Pathogenesis Related Protein

Legumes can meet their nitrogen requirements through root nodule symbiosis, which could also trigger plant systemic resistance against pests. The pea aphid Acyrthosiphon pisum , a legume pest, can harbour different facultative symbionts (FS) influencing various traits of their hosts. It is therefore worth determining if and how the symbionts of the plant and the aphid modulate their interaction. We used different pea aphid lines without FS or with a single one ( Hamiltonella defensa , Regiella insecticola, Serratia symbiotica ) to infest Medicago truncatula plants inoculated with Sinorhizobium meliloti (symbiotic nitrogen fixation, SNF) or supplemented with nitrate (non-inoculated, NI). The growth of SNF and NI plants was reduced by aphid infestation, while aphid weight (but not survival) was lowered on SNF compared to NI plants. Aphids strongly affected the plant nitrogen fixation depending on their symbiotic status, suggesting indirect relationships between aphid- and plant-associated microbes. Finally, all aphid lines triggered expression of Pathogenesis-Related Protein 1 ( PR1 ) and Proteinase Inhibitor (PI) , respective markers for salicylic and jasmonic pathways, in SNF plants, compared to only PR1 in NI plants. We demonstrate that the plant symbiotic status influences plant–aphid interactions while that of the aphid can modulate the amplitude of the plant's defence response.

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