scholarly journals The Glucocorticoid-Inducible GVG System Causes Severe Growth Defects in Both Root and Shoot of the Model Legume Lotus japonicus

2003 ◽  
Vol 16 (12) ◽  
pp. 1069-1076 ◽  
Author(s):  
Stig Uggerhøj Andersen ◽  
Cristina Cvitanich ◽  
Birgit Kristine Hougaard ◽  
Andreas Roussis ◽  
Mette Grønlund ◽  
...  
Keyword(s):  
Symbiotic Nitrogen Fixation ◽  
Lotus Japonicus ◽  
Inducible Promoter ◽  
Auxin Signaling ◽  
Model Legume ◽  
Growth Defects ◽  
The Past ◽  
Pericycle Cell ◽  
Expression Of Genes ◽  
Severe Growth

During the past decade, the legume Lotus japonicus has emerged as an important model system for study of symbiotic nitrogen fixation. Controlled expression of genes involved in symbiosis from an inducible promoter at specific time points would be a valuable tool for investigating gene function in L. japonicus. We have attempted to study the function of the putative transcription factors LjNDX and LjCPP1 by expression from the GVG inducible system. This study showed that the GVG system itself causes growth disturbances in L. japonicus. Shoot internode elongation and root pericycle cell division are affected when the chimeric GVG transcription factor is activated. We suggest that deficient auxin signaling could cause the phenotype observed and conclude that the GVG inducible system is not well suited for use in the model legume L. japonicus.

scholarly journals Medicago truncatulaZinc-Iron Permease6 provides zinc to rhizobia-infected nodule cells

2017 ◽  
Author(s):  
Isidro Abreu ◽  
Ángela Saéz ◽  
Rosario Castro-Rodríguez ◽  
Viviana Escudero ◽  
Benjamín Rodríguez-Haas ◽  
...  
Keyword(s):  
Symbiotic Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Zinc Transporters ◽  
Model Legume ◽  
Expression Levels ◽  
Growth Defects ◽  
Differentiation Zone ◽  
Infected Cells ◽  
Severe Growth ◽  
Infected Nodule

Abstract:Zinc is a micronutrient required for symbiotic nitrogen fixation. It has been proposed that in model legumeMedicago truncatula, zinc is delivered in a similar fashion as iron,i.e.by the root vasculature into the nodule and released in the infection/differentiation zone. There, zinc transporters must introduce this element into rhizobia-infected cells to metallate the apoproteins that use zinc as a cofactor.MtZIP6(Medtr4g083570) is aM. truncatulaZinc-Iron Permease (ZIP) that is expressed only in roots and nodules, with the highest expression levels in the infection/differentiation zone. Immunolocalization studies indicate that it is located in the plasma membrane of rhizobia-infected cells in the nodule. Down-regulatingMtZIP6expression levels with RNAi does not result in any strong phenotype when plants are being watered with mineral nitrogen. However, these silenced plants displayed severe growth defects when they depended on nitrogen fixed by their nodules, as a consequence of the loss of 80% of their nitrogenase activity. The reduction of this activity was not the result of iron not reaching the nodule, but an indirect effect of zinc being retained in the infection/differentiation zone and not reaching the cytosol of rhizobia-infected cells. These data are consistent with a model in which MtZIP6 would be responsible for zinc uptake by rhizobia-infected nodule cells in the infection/differentiation zone.

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 Expression Islands Clustered on the Symbiosis Island of the Mesorhizobium loti Genome

2004 ◽  
Vol 186 (8) ◽  
pp. 2439-2448 ◽  
Author(s):  
Toshiki Uchiumi ◽  
Takuji Ohwada ◽  
Manabu Itakura ◽  
Hisayuki Mitsui ◽  
Noriyuki Nukui ◽  
...  
Keyword(s):  
Acid Metabolism ◽  
Symbiotic Nitrogen Fixation ◽  
Transcriptional Profiling ◽  
Lotus Japonicus ◽  
Model Legume ◽  
Mesorhizobium Loti ◽  
Genome Region ◽  
Transcriptional Dynamics ◽  
Rhizobial Symbiosis ◽  
Highly Expressed Genes

ABSTRACT Rhizobia are symbiotic nitrogen-fixing soil bacteria that are associated with host legumes. The establishment of rhizobial symbiosis requires signal exchanges between partners in microaerobic environments that result in mutualism for the two partners. We developed a macroarray for Mesorhizobium loti MAFF303099, a microsymbiont of the model legume Lotus japonicus, and monitored the transcriptional dynamics of the bacterium during symbiosis, microaerobiosis, and starvation. Global transcriptional profiling demonstrated that the clusters of genes within the symbiosis island (611 kb), a transmissible region distinct from other chromosomal regions, are collectively expressed during symbiosis, whereas genes outside the island are downregulated. This finding implies that the huge symbiosis island functions as clustered expression islands to support symbiotic nitrogen fixation. Interestingly, most transposase genes on the symbiosis island were highly upregulated in bacteroids, as were nif, fix, fdx, and rpoN. The genome region containing the fixNOPQ genes outside the symbiosis island was markedly upregulated as another expression island under both microaerobic and symbiotic conditions. The symbiosis profiling data suggested that there was activation of amino acid metabolism, as well as nif-fix gene expression. In contrast, genes for cell wall synthesis, cell division, DNA replication, and flagella were strongly repressed in differentiated bacteroids. A highly upregulated gene in bacteroids, mlr5932 (encoding 1-aminocyclopropane-1-carboxylate deaminase), was disrupted and was confirmed to be involved in nodulation enhancement, indicating that disruption of highly expressed genes is a useful strategy for exploring novel gene functions in symbiosis.

scholarly journals Guidelines for Genetic Nomenclature and Community Governance for the Model Legume Medicago truncatula

2001 ◽  
Vol 14 (12) ◽  
pp. 1364-1367 ◽  
Author(s):  
Kathryn A. VandenBosch ◽  
Julia Frugoli
Keyword(s):  
Medicago Truncatula ◽  
Rapid Growth ◽  
Model System ◽  
Gene Nomenclature ◽  
Community Governance ◽  
Model Legume ◽  
The Past ◽  
Genetic Nomenclature ◽  
International Collaborations

At the 2nd Medicago meeting (a satellite of the 1999 IS-MPMI meeting in Amsterdam), investigators perceived a need for standardization of genetic nomenclature in Medicago truncatula, due to the rapid growth of research on this species in the past few years. Establishment of such standards grew out of discussions begun at this meeting and continued electronically throughout the M. truncatula community. The proposed standards presented here are the consensus results of those discussions. In addition to standards for gene nomenclature, a method for community governance and a website for cataloging gene names and submitting new ones are presented. The purpose of implementing these guidelines is to help maintain consistency in the literature, to avoid redundancy, to contribute to the accuracy of databases, and, in general, to aid the international collaborations that have made M. truncatula a model system for legume biology.

scholarly journals Characterization and Expression Analysis of Genes Encoding Phosphoenolpyruvate Carboxylase and Phosphoenolpyruvate Carboxylase Kinase of Lotus japonicus, a Model Legume

2003 ◽  
Vol 16 (4) ◽  
pp. 281-288 ◽  
Author(s):  
Tomomi Nakagawa ◽  
Tomoko Izumi ◽  
Mari Banba ◽  
Yosuke Umehara ◽  
Hiroshi Kouchi ◽  
...  
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Root Nodules ◽  
Expression Patterns ◽  
Phosphorylation Site ◽  
Lotus Japonicus ◽  
Specific Protein ◽  
Mrna Levels ◽  
Model Legume ◽  
Putative Phosphorylation Site

Phosphoenolpyruvate carboxylases (PEPCs), one form of which in each legume species plays a central role in the carbon metabolism in symbiotic root nodules, are activated through phosphorylation of a conserved residue by a specific protein kinase (PEPC-PK). We characterized the cDNAs for two PEPC isoforms of Lotus japonicus, an amide-translocating legume that forms determinate nodules. One gene encodes a nodule-enhanced form, which is more closely related to the PEPCs in amide-type indeterminate nodules than those in ureide-type determinate nodules. The other gene is expressed in shoots and roots at a low level. Both forms have the putative phosphorylation site, Ser11. We also isolated a cDNA and the corresponding genomic DNA for PEPC-PK of L. japonicus. The recombinant PEPC-PK protein expressed in Escherichia coli phosphorylated recombinant maize C4-form PEPC efficiently in vitro. The level of mRNA for PEPC-PK was high in root nodules, and those in shoots and roots were also significant. In situ hybridization revealed that the expression patterns of the transcripts for PEPC and PEPC-PK were similar in mature root nodules, but were different in emerging nodules. When L. japonicus seedlings were subjected to prolonged darkness and subsequent illumination, the activity of PEPC-PK and the mRNA levels of both PEPC and PEPC-PK in nodules decreased and then recovered, suggesting that they are regulated according to the amounts of photosynthates transported from shoots.

Recent Advances in the Molecular Genetics of The Model Legume Lotus japonicus

1997 ◽  
pp. 255-258
Author(s):  
Leif Schauser ◽  
Leszek Boron ◽  
Eloisa Pajuelo ◽  
Thomas Thykjær ◽  
Dorthe Danielsen ◽  
...  
Keyword(s):  
Molecular Genetics ◽  
Lotus Japonicus ◽  
Model Legume ◽  
Recent Advances

Arabidopsis mtHSC70-1 plays important roles in the establishment of COX-dependent respiration and redox homeostasis

2019 ◽  
Vol 70 (20) ◽  
pp. 5575-5590 ◽  
Author(s):  
Shan-Shan Wei ◽  
Wei-Tao Niu ◽  
Xiao-Ting Zhai ◽  
Wei-Qian Liang ◽  
Meng Xu ◽  
...  
Keyword(s):  
Alternative Oxidase ◽  
Redox Homeostasis ◽  
Superoxide Dismutase 1 ◽  
Respiratory Pathway ◽  
Cellular Processes ◽  
Growth Defects ◽  
Alternative Respiratory Pathway ◽  
Abnormal Mitochondria ◽  
Shock Proteins ◽  
Severe Growth

Abstract The 70 kDa heat shock proteins function as molecular chaperones and are involved in diverse cellular processes. However, the functions of the plant mitochondrial HSP70s (mtHSC70s) remain unclear. Severe growth defects were observed in the Arabidopsis thaliana mtHSC70-1 knockout lines, mthsc70-1a and mthsc70-1b. Conversely, the introduction of the mtHSC70-1 gene into the mthsc70-1a background fully reversed the phenotypes, indicating that mtHSC70-1 is essential for plant growth. The loss of mtHSC70-1 functions resulted in abnormal mitochondria and alterations to respiration because of an inhibition of the cytochrome c oxidase (COX) pathway and the activation of the alternative respiratory pathway. Defects in COX assembly were observed in the mtHSC70-1 knockout lines, leading to decreased COX activity. The mtHSC70-1 knockout plants have increased levels of reactive oxygen species (ROS). The introduction of the Mn-superoxide dismutase 1 (MSD1) or the catalase 1 (CAT1) gene into the mthsc70-1a plants decreased ROS levels, reduced the expression of alternative oxidase, and partially rescued growth. Taken together, our data suggest that mtHSC70-1 plays important roles in the establishment of COX-dependent respiration.

scholarly journals Redundant Roles of Tead1 and Tead2 in Notochord Development and the Regulation of Cell Proliferation and Survival

2008 ◽  
Vol 28 (10) ◽  
pp. 3177-3189 ◽  
Author(s):  
Atsushi Sawada ◽  
Hiroshi Kiyonari ◽  
Kanako Ukita ◽  
Noriyuki Nishioka ◽  
Yu Imuta ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Paraxial Mesoderm ◽  
Mouse Development ◽  
Lateral Plate ◽  
Growth Defects ◽  
Mouse Mutants ◽  
Severe Growth

ABSTRACT Four members of the TEAD/TEF family of transcription factors are expressed widely in mouse embryos and adult tissues. Although in vitro studies have suggested various roles for TEAD proteins, their in vivo functions remain poorly understood. Here we examined the role of Tead genes by generating mouse mutants for Tead1 and Tead2. Tead2 −/− mice appeared normal, but Tead1 −/−; Tead2 −/− embryos died at embryonic day 9.5 (E9.5) with severe growth defects and morphological abnormalities. At E8.5, Tead1 −/−; Tead2 −/− embryos were already small and lacked characteristic structures such as a closed neural tube, a notochord, and somites. Despite these overt abnormalities, differentiation and patterning of the neural plate and endoderm were relatively normal. In contrast, the paraxial mesoderm and lateral plate mesoderm were displaced laterally, and a differentiated notochord was not maintained. These abnormalities and defects in yolk sac vasculature organization resemble those of mutants for Yap, which encodes a coactivator of TEAD proteins. Moreover, we demonstrated genetic interactions between Tead1 and Tead2 and Yap. Finally, Tead1 −/−; Tead2 −/− embryos showed reduced cell proliferation and increased apoptosis. These results suggest that Tead1 and Tead2 are functionally redundant, use YAP as a major coactivator, and support notochord maintenance as well as cell proliferation and survival in mouse development.

scholarly journals Flavonoids and Isoflavonoids Biosynthesis in the Model Legume Lotus japonicus; Connections to Nitrogen Metabolism and Photorespiration

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 774 ◽  
Author(s):  
Margarita García-Calderón ◽  
Carmen M. Pérez-Delgado ◽  
Peter Palove-Balang ◽  
Marco Betti ◽  
Antonio J. Márquez
Keyword(s):  
Abiotic Stress ◽  
Nitrogen Metabolism ◽  
Lotus Japonicus ◽  
Regulatory Proteins ◽  
Phenylpropanoid Metabolism ◽  
Biological Processes ◽  
Model Legume ◽  
Different Types ◽  
Made In

Phenylpropanoid metabolism represents an important metabolic pathway from which originates a wide number of secondary metabolites derived from phenylalanine or tyrosine, such as flavonoids and isoflavonoids, crucial molecules in plants implicated in a large number of biological processes. Therefore, various types of interconnection exist between different aspects of nitrogen metabolism and the biosynthesis of these compounds. For legumes, flavonoids and isoflavonoids are postulated to play pivotal roles in adaptation to their biological environments, both as defensive compounds (phytoalexins) and as chemical signals in symbiotic nitrogen fixation with rhizobia. In this paper, we summarize the recent progress made in the characterization of flavonoid and isoflavonoid biosynthetic pathways in the model legume Lotus japonicus (Regel) Larsen under different abiotic stress situations, such as drought, the impairment of photorespiration and UV-B irradiation. Emphasis is placed on results obtained using photorespiratory mutants deficient in glutamine synthetase. The results provide different types of evidence showing that an enhancement of isoflavonoid compared to standard flavonol metabolism frequently occurs in Lotus under abiotic stress conditions. The advance produced in the analysis of isoflavonoid regulatory proteins by the use of co-expression networks, particularly MYB transcription factors, is also described. The results obtained in Lotus japonicus plants can be also extrapolated to other cultivated legume species, such as soybean, of extraordinary agronomic importance with a high impact in feeding, oil production and human health.

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