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 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 Whole-Genome Sequence of the Nitrogen-Fixing Symbiotic Rhizobium Mesorhizobium loti Strain TONO

2016 ◽  
Vol 4 (5) ◽  
Author(s):  
Yoshikazu Shimoda ◽  
Hideki Hirakawa ◽  
Shusei Sato ◽  
Kazuhiko Saeki ◽  
Makoto Hayashi
Keyword(s):  
Comparative Genomics ◽  
Genome Sequence ◽  
Lotus Japonicus ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Nitrogen Fixing ◽  
Model Legume ◽  
Mesorhizobium Loti ◽  
Symbiotic Properties

Mesorhizobium loti is the nitrogen-fixing microsymbiont for legumes of the genus Lotus . Here, we report the whole-genome sequence of a Mesorhizobium loti strain, TONO, which is used as a symbiont for the model legume Lotus japonicus . The whole-genome sequence of the strain TONO will be a solid platform for comparative genomics analyses and for the identification of genes responsible for the symbiotic properties of Mesorhizobium species.

scholarly journals Responses of a Model Legume Lotus japonicus to Lipochitin Oligosaccharide Nodulation Factors Purified from Mesorhizobium loti JRL501

2001 ◽  
Vol 14 (7) ◽  
pp. 848-856 ◽  
Author(s):  
Shinobu Niwa ◽  
Masayoshi Kawaguchi ◽  
Haruko Imaizumi-Anraku ◽  
Svetlana A. Chechetka ◽  
Masumi Ishizaka ◽  
...  
Keyword(s):  
High Performance ◽  
Molecular Genetic ◽  
Lotus Japonicus ◽  
Cytoplasmic Bridge ◽  
Cortical Cells ◽  
Model Legume ◽  
Mesorhizobium Loti ◽  
Root Hair Deformation ◽  
Early Nodulin ◽  
Microbe Interactions

Lotus japonicus has been proposed as a model legume for molecular genetic studies of symbiotic plant-microbe interactions leading to the fixation of atmospheric nitrogen. Lipochitin oligosaccharides (LCOs), or Nod factors, were isolated from the culture of Mesorhizobium loti strain JRL501 (MAFF303099), an efficient microsymbiont of L. japonicus B-129 cv. Gifu. High-performance liquid chromatography and mass spectrometric analyses allowed us to identify at least five different structures of LCOs that were produced by JRL501. The major component was NodMl-V(C18:1, Me, Cb, AcFuc), an N-acetyl-glucosamine pentamer in which the nonreducing residue is N-acylated with a C18:1 acyl moiety, N-methylated, and carries a carbamoyl group and the reducing N-acetyl-glucosamine residue is substituted with 4-O-acetyl-fucose. Additional novel LCO structures bearing fucose instead of acetyl-fucose at the reducing end were identified. Mixtures of these LCOs could elicit abundant root hair deformation on L. japonicus roots at a concentration of 10-7 to 10-9 M. Spot inoculation of a few nanograms of LCOs on L. japonicus roots induced the formation of nodule primordia in which the early nodulin genes, ENOD40 and ENOD2, were expressed in a tissue-specific manner. We also observed the formation of a cytoplasmic bridge (preinfection thread) in the swollen outermost cortical cells. This is the first description of cytoplasmic bridge formation by purified LCOs alone in a legume-forming determinate nodules.

scholarly journals Characterization of a Mesorhizobium loti α-Type Carbonic Anhydrase and Its Role in Symbiotic Nitrogen Fixation

2009 ◽  
Vol 191 (8) ◽  
pp. 2593-2600 ◽  
Author(s):  
Chrysanthi Kalloniati ◽  
Daniela Tsikou ◽  
Vasiliki Lampiri ◽  
Mariangela N. Fotelli ◽  
Heinz Rennenberg ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Carbonic Anhydrase ◽  
Mutant Strain ◽  
Symbiotic Nitrogen Fixation ◽  
Plant Traits ◽  
Nitrogenase Activity ◽  
Nodule Development ◽  
Free Living ◽  
Model Legume ◽  
Mesorhizobium Loti

ABSTRACT Carbonic anhydrase (CA) (EC 4.2.1.1) is a widespread enzyme catalyzing the reversible hydration of CO2 to bicarbonate, a reaction that participates in many biochemical and physiological processes. Mesorhizobium loti, the microsymbiont of the model legume Lotus japonicus, possesses on the symbiosis island a gene (msi040) encoding an α-type CA homologue, annotated as CAA1. In the present work, the CAA1 open reading frame from M. loti strain R7A was cloned, expressed, and biochemically characterized, and it was proven to be an active α-CA. The biochemical and physiological roles of the CAA1 gene in free-living and symbiotic rhizobia were examined by using an M. loti R7A disruption mutant strain. Our analysis revealed that CAA1 is expressed in both nitrogen-fixing bacteroids and free-living bacteria during growth in batch cultures, where gene expression was induced by increased medium pH. L. japonicus plants inoculated with the CAA1 mutant strain showed no differences in top-plant traits and nutritional status but consistently formed a higher number of nodules exhibiting higher fresh weight, N content, nitrogenase activity, and δ13C abundance. Based on these results, we propose that although CAA1 is not essential for nodule development and symbiotic nitrogen fixation, it may participate in an auxiliary mechanism that buffers the bacteroid periplasm, creating an environment favorable for NH3 protonation, thus facilitating its diffusion and transport to the plant. In addition, changes in the nodule δ13C abundance suggest the recycling of at least part of the HCO3 − produced by CAA1.

scholarly journals Tissue-Specific Transcriptome Analysis in Nodules of Lotus japonicus

2012 ◽  
Vol 25 (7) ◽  
pp. 869-876 ◽  
Author(s):  
Kojiro Takanashi ◽  
Hirokazu Takahashi ◽  
Nozomu Sakurai ◽  
Akifumi Sugiyama ◽  
Hideyuki Suzuki ◽  
...  
Keyword(s):  
Transcriptome Analysis ◽  
Root Nodules ◽  
Lotus Japonicus ◽  
Phenylpropanoid Pathway ◽  
Specific Expression ◽  
Model Legume ◽  
Tissue Specific ◽  
Highly Expressed Genes ◽  
Infected Cells ◽  
Nitrogen Nutrients

Legume plants can establish symbiotic nitrogen fixation (SNF) with rhizobia mostly in root nodules, where rhizobia-infected cells are accompanied by uninfected cells in a mosaic pattern. Inside the mature nodules of the legume, carbon and nitrogen nutrients between host plant cells and their resident bacteria are actively exchanged. To elucidate the metabolite dynamics relevant for SNF in nodules, three tissues from a nodule of a model legume, Lotus japonicus, were isolated using laser microdissesction, and transcriptome analysis was done by an oligoarray of 60-mer length representing 21,495 genes. In our tissue-specific profiling, many genes were identified as being expressed in nodules in a spatial-specific manner. Among them, genes coding for metabolic enzymes were classified according to their function, and detailed data analysis showed that a secondary metabolic pathway was highly activated in the nodule cortex. In particular, a number of metabolic genes for a phenylpropanoid pathway were found as highly expressed genes accompanied by those encoding putative transporters of secondary metabolites. These data suggest the involvement of a novel physiological function of phenylpropanoids in SNF. Moreover, five representative genes were selected, and detailed tissue-specific expression was characterized by promoter-β-glucuronidase experiments. Our results provide a new data source for investigation of both nodule differentiation and tissue-specific physiological functions in nodules.

scholarly journals Lotus japonicus alters in planta fitness of Mesorhizobium loti dependent on symbiotic nitrogen fixation

PLoS ONE ◽  
2017 ◽  
Vol 12 (9) ◽  
pp. e0185568 ◽  
Author(s):  
Kenjiro W. Quides ◽  
Glenna M. Stomackin ◽  
Hsu-Han Lee ◽  
Jeff H. Chang ◽  
Joel L. Sachs
Keyword(s):  
Nitrogen Fixation ◽  
Symbiotic Nitrogen Fixation ◽  
Lotus Japonicus ◽  
In Planta ◽  
Mesorhizobium Loti

Improved procedures for in vitro regeneration and for phenotypic analysis in the model legume Lotus japonicus

2005 ◽  
Vol 32 (6) ◽  
pp. 529 ◽  
Author(s):  
Ani Barbulova ◽  
Enrica D'Apuzzo ◽  
Alessandra Rogato ◽  
Maurizio Chiurazzi
Keyword(s):  
In Vitro Regeneration ◽  
Lotus Japonicus ◽  
Shoot Formation ◽  
Direct Somatic Embryogenesis ◽  
Phenotypic Analysis ◽  
Indirect Organogenesis ◽  
Model Legume ◽  
Mesorhizobium Loti ◽  
Efficient Gene

As a prerequisite for the development of an efficient gene transfer methodology, the possibility of inducing direct somatic embryogenesis in Lotus japonicus (Regel) K. Larsen explants was investigated. Petiole bases, cotyledons, hypocotyls and stem segments were cultivated in the presence of different amounts of benzylaminopurine (BAP) and / or thidiazuron (TDZ). Regeneration was achieved differentially in the different explants and a higher efficiency of shoot formation was obtained with TDZ. By maintaining the same TDZ regime a second cycle of morphogenesis was achieved and the histological analysis of these structures indicated unambiguously their somatic embryogenic nature. Thidiazuron was also tested as an agent to improve the kinetics of shoot formation in a Lotus japonicus transformation–regeneration procedure based on indirect organogenesis. A very significant, highly reproducible, increase in the rate of the shoot formation was observed in independent transformation experiments. We also present an extensive analysis of the feasibility and reproducibility of an in vitro procedure, which can be very useful for the screening of symbiotic phenotypes in transgenic Lotus plants and for the analysis of the cascade of molecular and cytological events occurring soon after Mesorhizobium loti infection.

scholarly journals A Novel Fix¯ Symbiotic Mutant of Lotus japonicus, Ljsym105, Shows Impaired Development and Premature Deterioration of Nodule Infected Cells and Symbiosomes

2006 ◽  
Vol 19 (7) ◽  
pp. 780-788 ◽  
Author(s):  
Md. Shakhawat Hossain ◽  
Yosuke Umehara ◽  
Hiroshi Kouchi
Keyword(s):  
Nitrogen Deficiency ◽  
Lotus Japonicus ◽  
Nodule Development ◽  
Acetylene Reduction Activity ◽  
Nitrogen Fixing ◽  
Wild Type ◽  
Electron Microscopic ◽  
Model Legume ◽  
Mesorhizobium Loti ◽  
Infected Cells

Nitrogen-fixing symbiosis between legume plants and rhizobia is established through complex interactions between two symbiotic partners. To identify the host legume genes that play crucial roles in such interactions, we isolated a novel Fix¯ mutant, Ljsym105, from a model legume Lotus japonicus MG-20. The Ljsym105 plants displayed nitrogen-deficiency symptoms after inoculation with Mesorhizobium loti under nitrogen-free conditions, but their growth recovered when supplied with nitrogen-rich nutrients. Ljsym105 was recessive and monogenic and mapped on the upper portion of chromosome 4. The mutant Ljsym105 formed an increased number of small and pale-pink nodules. Nitrogenase (acetylene reduction) activity per nodule fresh weight was low but retained more than 50% of that of the wild-type nodules. Light and electron microscopic observations revealed that the Ljsym105 nodule infected cells were significantly smaller than those of wild-type plants, contained enlarged symbiosomes with multiple bacteroids, and underwent deterioration of the symbiosomes prematurely as well as disintegration of the whole infected cell cytoplasm. These results indicate that the ineffectiveness of the Ljsym105 nodules is primarily due to impaired growth of infected cells accompanied with the premature senescence induced at relatively early stages of nodule development. These symbiotic phenotypes are discussed in respect to possible functions of the LjSym105 locus in the symbiotic interactions required for establishment of the nitrogen-fixing symbiosis.

scholarly journals Mutants of Lotus japonicus deficient in flavonoid biosynthesis

2021 ◽  
Vol 134 (2) ◽  
pp. 341-352
Author(s):  
Toshio Aoki ◽  
Masayoshi Kawaguchi ◽  
Haruko Imaizumi-Anraku ◽  
Shoichiro Akao ◽  
Shin-ichi Ayabe ◽  
...  
Keyword(s):  
Anthocyanin Biosynthesis ◽  
Lotus Japonicus ◽  
Flavonoid Biosynthesis ◽  
Anthocyanin Accumulation ◽  
Type B ◽  
Wild Type ◽  
Ems Mutagenesis ◽  
Model Legume ◽  
Mesorhizobium Loti ◽  
Wild Accessions

AbstractSpatiotemporal features of anthocyanin accumulation in a model legumeLotus japonicus(Regel) K.Larsen were elucidated to develop criteria for the genetic analysis of flavonoid biosynthesis. Artificial mutants and wild accessions, with lower anthocyanin accumulation in the stem than the standard wild type (B-129 ‘Gifu’), were obtained by ethyl methanesulfonate (EMS) mutagenesis and from a collection of wild-grown variants, respectively. The loci responsible for the green stem of the mutants were named asVIRIDICAULIS(VIC). Genetic and chemical analysis identified two loci, namely,VIC1andVIC2, required for the production of both anthocyanins and proanthocyanidins (condensed tannins), and two loci, namely,VIC3andVIC4, required for the steps specific to anthocyanin biosynthesis. A mutation inVIC5significantly reduced the anthocyanin accumulation. These mutants will serve as a useful system for examining the effects of anthocyanins and proanthocyanidins on the interactions with herbivorous pests, pathogenic microorganisms and nitrogen-fixing symbiotic bacteria,Mesorhizobium loti.

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.

Sign in / Sign up

Export Citation Format

Share Document