scholarly journals Medicago truncatulaMOT1.3 is a plasma membrane molybdenum transporter required for nitrogenase activity in root nodules

2017 ◽  
Author(s):  
Manuel Tejada-Jiménez ◽  
Patricia Gil-Díez ◽  
Javier León-Mediavilla ◽  
Jiangqi Wen ◽  
Kirankumar S. Mysore ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
List Type ◽  
Knockout Mutant ◽  
Model Legume ◽  
Molybdate Transport ◽  
The One ◽  
Iron Molybdenum Cofactor

SummaryMolybdenum, as a component of the iron-molybdenum cofactor of nitrogenase, is essential for symbiotic nitrogen fixation. This nutrient has to be provided by the host plant through molybdate transporters.Members of the molybdate transporters family MOT1 were identified in the model legumeMedicago truncatulaand their expression in nodules determined. Yeast toxicity assays, confocal microscopy, and phenotypical characterization of aTnt1insertional mutant line were carried out in the oneM. truncatulaMOT1 family member expressed specifically in nodules.Among the five MOT1 members present inM. truncatulagenome,MtMOT1.3is the only one uniquely expressed in nodules. MtMOT1.3 shows molybdate transport capabilities when expressed in yeast. Immunolocalization studies revealed that MtMOT1.3 is located in the plasma membrane of nodule cells. Amot1.3-1knockout mutant showed an impaired growth concomitant with a reduction in nitrogenase activity. This phenotype was rescued by increasing molybdate concentrations in the nutritive solution, or upon addition of an assimilable nitrogen source. Furthermore,mot1.3-1plants transformed with a functional copy ofMtMOT1.3showed a wild type-like phenotype.These data are consistent with a model in which MtMOT1.3 would be responsible for introducing molybdate into nodule cells, which will be later used to synthesize functional nitrogenase.

scholarly journals Paraburkholderia phymatum Homocitrate Synthase NifV Plays a Key Role for Nitrogenase Activity during Symbiosis with Papilionoids and in Free-Living Growth Conditions

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 952
Author(s):  
Paula Bellés-Sancho ◽  
Martina Lardi ◽  
Yilei Liu ◽  
Sebastian Hug ◽  
Marta Adriana Pinto-Carbó ◽  
...  
Keyword(s):  
Nitrogenase Activity ◽  
Root Nodules ◽  
Growth Conditions ◽  
Lysine Biosynthesis ◽  
Metabolome Analysis ◽  
Plant Host ◽  
Free Living ◽  
Bacterial Enzyme ◽  
Homocitrate Synthase ◽  
Iron Molybdenum Cofactor

Homocitrate is an essential component of the iron-molybdenum cofactor of nitrogenase, the bacterial enzyme that catalyzes the reduction of dinitrogen (N2) to ammonia. In nitrogen-fixing and nodulating alpha-rhizobia, homocitrate is usually provided to bacteroids in root nodules by their plant host. In contrast, non-nodulating free-living diazotrophs encode the homocitrate synthase (NifV) and reduce N2 in nitrogen-limiting free-living conditions. Paraburkholderia phymatum STM815 is a beta-rhizobial strain, which can enter symbiosis with a broad range of legumes, including papilionoids and mimosoids. In contrast to most alpha-rhizobia, which lack nifV, P. phymatum harbors a copy of nifV on its symbiotic plasmid. We show here that P. phymatum nifV is essential for nitrogenase activity both in root nodules of papilionoid plants and in free-living growth conditions. Notably, nifV was dispensable in nodules of Mimosa pudica despite the fact that the gene was highly expressed during symbiosis with all tested papilionoid and mimosoid plants. A metabolome analysis of papilionoid and mimosoid root nodules infected with the P. phymatum wild-type strain revealed that among the approximately 400 measured metabolites, homocitrate and other metabolites involved in lysine biosynthesis and degradation have accumulated in all plant nodules compared to uninfected roots, suggesting an important role of these metabolites during symbiosis.

Characterization of an ineffective actinorhizal microsymbiont, Frankia sp. EuI1 (Actinomycetales)

1980 ◽  
Vol 26 (9) ◽  
pp. 1072-1089 ◽  
Author(s):  
Dwight Baker ◽  
William Newcomb ◽  
John G. Torrey
Keyword(s):  
Host Range ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Host Cells ◽  
Vesicle Formation ◽  
Nitrogen Fixing ◽  
Elaeagnus Umbellata

The actinomycete, Frankia sp. EuI1, isolated from root nodules of Elaeagnus umbellata is an infective endophyte but which lacks the ability to form an effective nitrogen-fixing symbiosis with its host. This ineffective organism can be distinguished easily from other frankiae, in vitro, on the basis of size, morphology, and the elaboration of a diffusible pigment. Cross-inoculation studies indicated that the host range of this symbiont is narrow and probably restricted to the Elaeagnaceae. In all cases of nodulation the symbiosis never developed nitrogenase activity and the microsymbiont never produced endophytic vesicles within the infected host cells. Sporangia were produced in vivo and in vitro so the morphogenetic block is apparently restricted to vesicle formation.

scholarly journals MtMOT1.2 is responsible for molybdate supply toMedicago truncatulanodules

2018 ◽  
Author(s):  
Patricia Gil-Díez ◽  
Manuel Tejada-Jiménez ◽  
Javier León-Mediavilla ◽  
Jiangqi Wen ◽  
Kirankumar S. Mysore ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Symbiotic Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Reductase Activity ◽  
Root Nodules ◽  
Loss Of Function ◽  
Intracellular Membrane ◽  
Wild Type ◽  
Endodermal Cells ◽  
Iron Molybdenum Cofactor

ABSTRACTSymbiotic nitrogen fixation in legume root nodules requires a steady supply of molybdenum for synthesis of the iron-molybdenum cofactor of nitrogenase. This nutrient has to be provided by the host plant from the soil, crossing several symplastically disconnected compartments through molybdate transporters, including members of the MOT1 family. MtMOT1.2 is aMedicago truncatulaMOT1 family member located in the endodermal cells in roots and nodules. Immunolocalization of a tagged MtMOT1.2 indicates that it is associated to the plasma membrane and to intracellular membrane systems, where it would be transporting molybdate towards the cytosol, as indicated in yeast transport assays. A loss-of-functionmot1.2-1mutant showed reduced growth compared to wild-type plants when nitrogen fixation was required, but not when nitrogen was provided as nitrate. While no effect on molybdenum-dependent nitrate reductase activity was observed, nitrogenase activity was severely affected, explaining the observed difference of growth depending on nitrogen source. This phenotype was the result of molybdate not reaching the nitrogen-fixing nodules, since genetic complementation with a wild-typeMtMOT1.2gene or molybdate-fortification of the nutrient solution, both restored wild-type levels of growth and nitrogenase activity. These results support a model in which MtMOT1.2 would mediate molybdate delivery by the vasculature into the nodules.

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 Medicago truncatulaMolybdate Transporter type 1 (MtMOT1.3) is a plasma membrane molybdenum transporter required for nitrogenase activity in root nodules under molybdenum deficiency

2017 ◽  
Vol 216 (4) ◽  
pp. 1223-1235 ◽  
Author(s):  
Manuel Tejada-Jiménez ◽  
Patricia Gil-Díez ◽  
Javier León-Mediavilla ◽  
Jiangqi Wen ◽  
Kirankumar S. Mysore ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Nitrogenase Activity ◽  
Root Nodules

STUDIES IN CONGENITAL GENERALIZED LIPODYSTROPHY

1973 ◽  
Vol 72 (3) ◽  
pp. 495-505 ◽  
Author(s):  
Oddmund Søvik ◽  
Svein Oseid
Keyword(s):  
Biological Activity ◽  
Insulin Response ◽  
Epididymal Adipose Tissue ◽  
Large Individual ◽  
Immunoreactive Insulin ◽  
List Type ◽  
Glucose Load ◽  
Congenital Generalized Lipodystrophy ◽  
The One

ABSTRACT The biological activity of plasma insulin from 4 cases of congenital generalized lipodystrophy has been studied, using rat diaphragm and epididymal adipose tissue in vivo. The results are compared with previous data on plasma immunoreactive insulin obtained in these patients. 2 of the 4 cases exhibited unusually high biological insulin activities during the fasting state as well as after an intravenous (iv) glucose load. In the fat pad assay activities as high as 10 000 μU insulin per ml were observed. During childhood the biological insulin activities were generally high, although there were large individual variations. However, in the one case studied after the age of puberty, the insulin response to a glucose load was negligible. Taken together, the biological and immunological activities observed strongly suggest the presence of pancreatic insulin in these patients. It appears that the circulating insulin has a fully biological activity. The decreasing insulin activities after cessation of growth are in agreement with the appearance of frank diabetes at this time.

Role of Exosomes in the Exchange of Spermatozoa after Leaving the Seminiferous Tubule: A Review

2020 ◽  
Vol 21 (5) ◽  
pp. 330-338
Author(s):  
Luming Wu ◽  
Yuan Ding ◽  
Shiqiang Han ◽  
Yiqing Wang
Keyword(s):  
Drug Delivery ◽  
Plasma Membrane ◽  
Seminiferous Tubule ◽  
Metabolic Diseases ◽  
Inflammatory Diseases ◽  
Multivesicular Bodies ◽  
Extensive Search ◽  
Neurological Research ◽  
The One

Background: Exosomes are extracellular vesicles (EVs) released from cells upon fusion of an intermediate endocytic compartment with the plasma membrane. They refer to the intraluminal vesicles released from the fusion of multivesicular bodies with the plasma membrane. The contents and number of exosomes are related to diseases such as metabolic diseases, cancer and inflammatory diseases. Exosomes have been used in neurological research as a drug delivery tool and also as biomarkers for diseases. Recently, exosomes were observed in the seminal plasma of the one who is asthenozoospermia, which can affect sperm motility and capacitation. Objective: The main objective of this review is to deeply discuss the role of exosomes in spermatozoa after leaving the seminiferous tubule. Methods: We conducted an extensive search of the literature available on relationships between exosomes and exosomes in spermatozoa on the bibliographic database. Conclusion: : This review thoroughly discussed the role that exosomes play in the exchange of spermatozoa after leaving the seminiferous tubule and its potential as a drug delivery tool and biomarkers for diseases as well.

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