scholarly journals Differential Effects of Combined N Sources on Early Steps of the Nod Factor–Dependent Transduction Pathway in Lotus japonicus

2007 ◽  
Vol 20 (8) ◽  
pp. 994-1003 ◽  
Author(s):  
Ani Barbulova ◽  
Alessandra Rogato ◽  
Enrica D'Apuzzo ◽  
Selim Omrane ◽  
Maurizio Chiurazzi
Keyword(s):  
Root Nodules ◽  
Lotus Japonicus ◽  
Small Scale ◽  
Nodule Formation ◽  
Inhibitory Effects ◽  
Nod Factor ◽  
Mesorhizobium Loti ◽  
N Sources ◽  
N Starvation ◽  
And Function

The development of nitrogen-fixing nodules in legumes is induced by perception of lipochitin-oligosaccharide signals secreted by a bacterial symbiont. Nitrogen (N) starvation is a prerequisite for the formation, development, and function of root nodules, and high levels of combined N in the form of nitrate or ammonium can completely abolish nodule formation. We distinguished between nitrate and ammonium inhibitory effects by identifying when and where these combined N sources interfere with the Nod-factor-induced pathway. Furthermore, we present a small-scale analysis of the expression profile, under different N conditions, of recently identified genes involved in the Nod-factor-induced pathway. In the presence of high levels of nitrate or ammonium, the NIN gene fails to be induced 24 h after the addition of Nod factor compared with plants grown under N-free conditions. This induction is restored in the hypernodulating nitrate-tolerant har1-3 mutant only in the presence of 10 and 20 mM KNO3. These results were confirmed in Lotus plants inoculated with Mesorhizobium loti. NIN plays a key role in the nodule organogenesis program and its downregulation may represent a crucial event in the nitrate-dependent pathway leading to the inhibition of nodule organogenesis.

scholarly journals Mesorhizobium loti Produces nodPQ-Dependent Sulfated Cell Surface Polysaccharides

2006 ◽  
Vol 188 (24) ◽  
pp. 8560-8572 ◽  
Author(s):  
Guy E. Townsend ◽  
Lennart S. Forsberg ◽  
David H. Keating
Keyword(s):  
Growth Rate ◽  
Cell Surface ◽  
Capsular Polysaccharide ◽  
Physiological Function ◽  
Root Nodules ◽  
Lotus Japonicus ◽  
Sulfated Polysaccharides ◽  
Nodule Formation ◽  
Mesorhizobium Loti ◽  
Surface Polysaccharides

ABSTRACT Leguminous plants and bacteria from the family Rhizobiaceae form a symbiotic relationship, which culminates in novel plant structures called root nodules. The indeterminate symbiosis that forms between Sinorhizobium meliloti and alfalfa requires biosynthesis of Nod factor, a β-1,4-linked lipochitooligosaccharide that contains an essential 6-O-sulfate modification. S. meliloti also produces sulfated cell surface polysaccharides, such as lipopolysaccharide (LPS). The physiological function of sulfated cell surface polysaccharides is unclear, although mutants of S. meliloti with reduced LPS sulfation exhibit symbiotic abnormalities. Using a bioinformatic approach, we identified a homolog of the S. meliloti carbohydrate sulfotransferase, LpsS, in Mesorhizobium loti. M. loti participates in a determinate symbiosis with the legume Lotus japonicus. We showed that M. loti produces sulfated forms of LPS and capsular polysaccharide (KPS). To investigate the physiological function of sulfated polysaccharides in M. loti, we identified and disabled an M. loti homolog of the sulfate-activating genes, nodPQ, which resulted in undetectable amounts of sulfated cell surface polysaccharides and a cysteine auxotrophy. We concomitantly disabled an M. loti cysH homolog, which disrupted cysteine biosynthesis without reducing cell surface polysaccharide sulfation. Our experiments demonstrated that the nodPQ mutant, but not the cysH mutant, showed an altered KPS structure and a diminished ability to elicit nodules on its host legume, Lotus japonicus. Interestingly, the nodPQ mutant also exhibited a more rapid growth rate and appeared to outcompete wild-type M. loti for nodule colonization. These results suggest that sulfated cell surface polysaccharides are required for optimum nodule formation but limit growth rate and nodule colonization in M. loti.

scholarly journals ALotus japonicusE3 ligase interacts with the Nod factor receptor 5 and positively regulates nodulation

2018 ◽  
Author(s):  
Daniela Tsikou ◽  
Estrella E. Ramirez ◽  
Ioanna S. Psarrakou ◽  
Jaslyn E. Wong ◽  
Dorthe B. Jensen ◽  
...  
Keyword(s):  
Lotus Japonicus ◽  
E3 Ligase ◽  
Kinase Domain ◽  
Plant Interactions ◽  
Post Translational Modification ◽  
Direct Role ◽  
Nod Factor ◽  
Mesorhizobium Loti ◽  
Signaling Systems ◽  
Nodulation Capacity

SUMMARYPost-translational modification of receptor proteins is involved in activation and de-activation of signaling systems in plants. Both ubiquitination and deubiquitination have been implicated in plant interactions with pathogens and symbionts. Here we presentLjPUB13, a PUB-ARMADILLO repeat E3 ligase that specifically ubiquitinates the kinase domain of the Nod Factor receptor NFR5 and has a direct role in nodule organogenesis events inLotus japonicus. Phenotypic analyses of three LORE1 retroelement insertion plant lines revealed thatpub13plants display delayed and reduced nodulation capacity and retarded growth.LjPUB13expression is spatially regulated during symbiosis withMesorhizobium loti, with increased levels in young developing nodules. Thus,LjPUB13 is an E3 ligase with a positive regulatory role during the initial stages of nodulation inL. japonicus.

scholarly journals A plant chitinase controls cortical infection thread progression and nitrogen-fixing symbiosis

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Anna Malolepszy ◽  
Simon Kelly ◽  
Kasper Kildegaard Sørensen ◽  
Euan Kevin James ◽  
Christina Kalisch ◽  
...  
Keyword(s):  
Root Nodules ◽  
Lotus Japonicus ◽  
Positional Information ◽  
Dependent Manner ◽  
Nitrogen Fixing ◽  
Nod Factors ◽  
Nod Factor ◽  
Infection Threads ◽  
Bacterial Mutants ◽  
Multicellular Organisms

Morphogens provide positional information and their concentration is key to the organized development of multicellular organisms. Nitrogen-fixing root nodules are unique organs induced by Nod factor-producing bacteria. Localized production of Nod factors establishes a developmental field within the root where plant cells are reprogrammed to form infection threads and primordia. We found that regulation of Nod factor levels by Lotus japonicus is required for the formation of nitrogen-fixing organs, determining the fate of this induced developmental program. Our analysis of plant and bacterial mutants shows that a host chitinase modulates Nod factor levels possibly in a structure-dependent manner. In Lotus, this is required for maintaining Nod factor signalling in parallel with the elongation of infection threads within the nodule cortex, while root hair infection and primordia formation are not influenced. Our study shows that infected nodules require balanced levels of Nod factors for completing their transition to functional, nitrogen-fixing organs.

scholarly journals T-DNA Tagging of Nodulation- and Root-Related Genes in Lotus japonicus: Expression Patterns and Potential for Promoter Trapping and Insertional Mutagenesis

1999 ◽  
Vol 12 (4) ◽  
pp. 275-284 ◽  
Author(s):  
Luca Martirani ◽  
Jiri Stiller ◽  
Rossana Mirabella ◽  
Flora Alfano ◽  
Alessandro Lamberti ◽  
...  
Keyword(s):  
Lateral Root ◽  
Insertional Mutagenesis ◽  
High Efficiency ◽  
Expression Patterns ◽  
Lotus Japonicus ◽  
Selection Strategy ◽  
Nodule Formation ◽  
Mesorhizobium Loti ◽  
Root Organogenesis ◽  
Gusa Gene

High-efficiency transformation of the autogamous diploid legume Lotus japonicus by means of Agrobacterium rhizogenes was used to develop plant lines expressing a promoter-less gusA gene in a nodulation- or lateral root-associated manner. The approach exploits the putatively preferential integration of T-DNA into actively transcribed regions, thereby providing an enrichment for gene tagging events associated with the quickly assayable activation of a gusA promoter-less construct. Taking advantage of this enrichment and selection strategy, a T-DNA tagging program was initiated and screening for β-glucuronidase (GUS) activity was performed on root clones isolated after transformation with a gusA-promoter-less binary vector. The aim of this approach is the identification of genes involved in nodule formation induced by Mesorhizobium loti, lateral root organogenesis, and the eventual isolation of corresponding mutants. A large collection (220) of GUS-positive transformants showing a variety of expression patterns in different regions of roots and nodules was obtained; a preliminary molecular characterization of these plants is presented.

scholarly journals The role of microRNAs in the legume–Rhizobium nitrogen-fixing symbiosis

2020 ◽  
Vol 71 (5) ◽  
pp. 1668-1680 ◽  
Author(s):  
Nhung T Hoang ◽  
Katalin Tóth ◽  
Gary Stacey
Keyword(s):  
Vascular System ◽  
Regulation Of Gene Expression ◽  
Lotus Japonicus ◽  
Nodule Formation ◽  
Nitrogen Fixing ◽  
Rna Molecules ◽  
Physiological Processes ◽  
Leaf Tissues ◽  
And Function

Abstract Under nitrogen starvation, most legume plants form a nitrogen-fixing symbiosis with Rhizobium bacteria. The bacteria induce the formation of a novel organ called the nodule in which rhizobia reside as intracellular symbionts and convert atmospheric nitrogen into ammonia. During this symbiosis, miRNAs are essential for coordinating the various plant processes required for nodule formation and function. miRNAs are non-coding, endogenous RNA molecules, typically 20–24 nucleotides long, that negatively regulate the expression of their target mRNAs. Some miRNAs can move systemically within plant tissues through the vascular system, which mediates, for example, communication between the stem/leaf tissues and the roots. In this review, we summarize the growing number of miRNAs that function during legume nodulation focusing on two model legumes, Lotus japonicus and Medicago truncatula, and two important legume crops, soybean (Glycine max) and common bean (Phaseolus vulgaris). This regulation impacts a variety of physiological processes including hormone signaling and spatial regulation of gene expression. The role of mobile miRNAs in regulating legume nodule number is also highlighted.

scholarly journals Natural variation identifies a Pxy gene controlling root vascular organization and formation of nodules and lateral roots in Lotus japonicus

2020 ◽  
Author(s):  
Yasuyuki Kawaharada ◽  
Niels Sandal ◽  
Vikas Gupta ◽  
Haojie Jin ◽  
Maya Kawaharada ◽  
...  
Keyword(s):  
Lateral Root ◽  
Reverse Genetics ◽  
De Novo ◽  
Lateral Roots ◽  
Lotus Japonicus ◽  
Nodule Formation ◽  
Mesorhizobium Loti ◽  
Genetic Overlap ◽  
Natural Variants ◽  
Trait Locus

AbstractForward and reverse genetics using the model legumes Lotus japonicus and Medicago truncatula have been instrumental for identifying the essential genes governing legume-rhizobial symbiosis. However, little is known about the effects of intraspecific variation on symbiotic signaling. The Lotus accessions Gifu and MG20 show differentiated phenotypic responses to the Mesorhizobium loti exoU mutant that produces truncated exopolysaccharides. Using Quantitative Trait Locus sequencing (QTL-seq), we identify the Pxy gene as a component of this differential exoU response. Lotus Pxy encodes a leucine-rich-repeat kinase similar to Arabidopsis PXY, which regulates stem vascular development. We show that Lotus pxy insertion mutants display defects in root vascular organization, as well as lateral root and nodule formation. Our work links Pxy to de novo organogenesis in the root, highlights the genetic overlap between regulation of lateral root and nodule formation, and demonstrates that specific natural variants of Pxy differentially affect nodulation signaling.

scholarly journals Suppression of Root Nodule Formation by Artificial Expression of the TrEnodDR1 (Coat Protein of White clover cryptic virus 1) Gene in Lotus japonicus

2005 ◽  
Vol 18 (10) ◽  
pp. 1069-1080 ◽  
Author(s):  
Mitsumi Nakatsukasa-Akune ◽  
Kenji Yamashita ◽  
Yoshikazu Shimoda ◽  
Toshiki Uchiumi ◽  
Mikiko Abe ◽  
...  
Keyword(s):  
Coat Protein ◽  
White Clover ◽  
Root Nodules ◽  
Lotus Japonicus ◽  
Specific Inhibitor ◽  
Nodule Formation ◽  
Model Legume ◽  
Root Nodulation ◽  
Cryptic Virus ◽  
Endogenous Aba

TrEnodDR1 (Trifolium repens early nodulin downregulation 1) encodes a coat protein of White clover cryptic virus 1. Its expression in white clover was down-regulated at the time when root nodules formed. We surmised that its artificial expression would interfere with root nodulation. Therefore, we investigated the effects of its artificial expression on the growth and root nodulation of Lotus japonicus (a model legume). Transformants were prepared by Agrobacterium spp.-mediated transformation. The growth of transformants was reduced and the number of root nodules per unit root length was greatly decreased relative to control. The concentration of endogenous abscisic acid (ABA), which controls nodulation, increased in plants containing TrEnodDR1. These phenotypes clearly were canceled by treatment with abamine, a specific inhibitor of ABA biosynthesis. The increase in endogenous ABA concentration explained the reduced stomatal aperture and the deformation of root hairs in response to inoculation of transgenic L. japonicus with Mesorhizobium loti. Transcriptome comparison between TrEnodDR1 transformants and control plants showed clearly enhanced expression levels of various defense response genes in transformants. These findings suggest that TrEnodDR1 suppresses nodulation by increasing the endogenous ABA concentration, perhaps by activating the plant's innate immune response. This is the first report of the suppression of nodulation by the artificial expression of a virus coat protein gene.

scholarly journals Lotus japonicus Forms Early Senescent Root Nodules with Rhizobium etli

2001 ◽  
Vol 14 (2) ◽  
pp. 173-180 ◽  
Author(s):  
Mari Banba ◽  
Abu-Baker M. Siddique ◽  
Hiroshi Kouchi ◽  
Katsura Izui ◽  
Shingo Hata
Keyword(s):  
Root Nodules ◽  
Nitrogen Deficiency ◽  
Lotus Japonicus ◽  
Acetylene Reduction Activity ◽  
Rhizobium Etli ◽  
Transcription Activator ◽  
Membrane Structures ◽  
Mesorhizobium Loti ◽  
Reduction Activity ◽  
Infected Cells

Mesorhizobium loti and Rhizobium etli are microsymbionts of the Lotus and Phaseolus spp., respectively, and secrete essentially the same Nod factors. Lotus japonicus efficiently formed root nodules with R. etli CE3, irrespective of the presence or absence of a flavonoid-independent transcription activator nodD gene. On a nitrogen-free medium, however, the host plant inoculated with R. etli showed a severe nitrogen deficiency symptom. Initially, the nodules formed with R. etli were pale pink and leghemoglobin mRNA was detectable at significant levels. Nevertheless, the nodules became greenish with time. Acetylene-reduction activity of nodules formed with R. etli was comparable with that formed by M. loti 3 weeks postinoculation, but thereafter it decreased rapidly. The nodules formed with R. etli contained much more starch granules than those formed with M. loti. R. etli developed into bacteroids in the L. japonicus nodules, although the density of bacteroids in the infected cells was lower than that in the nodules formed with M. loti. The nodules formed with R. etli were of the early senescence type, in that membrane structures were drastically disintegrated in the infected cells of the greenish nodules. Thus, L. japonicus started and then ceased a symbiotic relationship with R. etli at the final stage.

scholarly journals Expressed Sequence Tags from Roots and Nodule Primordia of Lotus japonicus Infected with Mesorhizobium loti

2002 ◽  
Vol 15 (4) ◽  
pp. 376-379 ◽  
Author(s):  
Carsten Poulsen ◽  
Lone Pødenphant
Keyword(s):  
Expressed Sequence Tags ◽  
Messenger Rna ◽  
Root Nodules ◽  
Lotus Japonicus ◽  
Cdna Expression Library ◽  
Expression Library ◽  
Mesorhizobium Loti ◽  
Pcr Products ◽  
Plant Genes ◽  
Expressed Sequence

Messenger RNA from young Lotus japonicus roots carrying root nodule primordia appearing after inoculation with Mesorhizobium loti bacteria were used to construct a cDNA expression library. Single-pass sequencing employing colony-polymerase chain reaction (PCR) and analysis of PCR products established a total of 2,397 new expressed sequence tags (ESTs). We have putatively identified 1,236 known and 484 hypothetical proteins coded by the corresponding mRNAs. The remaining cDNAs are unknown (316) or redundant overlapping cDNAs (361). We hope that this batch of ESTs will assist in the recognition of plant genes involved during development of nitrogen-fixing root nodules.

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