scholarly journals Metabolomic Profiling of Bradyrhizobium diazoefficiens-Induced Root Nodules Reveals Both Host Plant-Specific and Developmental Signatures

2016 ◽  
Vol 17 (6) ◽  
pp. 815 ◽  
Author(s):  
Martina Lardi ◽  
Valérie Murset ◽  
Hans-Martin Fischer ◽  
Socorro Mesa ◽  
Christian Ahrens ◽  
...  
Keyword(s):  
Host Plant ◽  
Root Nodules ◽  
Metabolomic Profiling

scholarly journals The rhizobial autotransporter determines the symbiotic nitrogen fixation activity of Lotus japonicus in a host-specific manner

2020 ◽  
Vol 117 (3) ◽  
pp. 1806-1815 ◽  
Author(s):  
Yoshikazu Shimoda ◽  
Yuki Nishigaya ◽  
Hiroko Yamaya-Ito ◽  
Noritoshi Inagaki ◽  
Yosuke Umehara ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Host Plant ◽  
Symbiotic Nitrogen Fixation ◽  
Root Nodules ◽  
Lotus Japonicus ◽  
Dependent Manner ◽  
Strain Specificity ◽  
Passenger Domain ◽  
Aspartic Peptidase ◽  
Specific Manner

Leguminous plants establish endosymbiotic associations with rhizobia and form root nodules in which the rhizobia fix atmospheric nitrogen. The host plant and intracellular rhizobia strictly control this symbiotic nitrogen fixation. We recently reported a Lotus japonicus Fix− mutant, apn1 (aspartic peptidase nodule-induced 1), that impairs symbiotic nitrogen fixation. APN1 encodes a nodule-specific aspartic peptidase involved in the Fix− phenotype in a rhizobial strain-specific manner. This host-strain specificity implies that some molecular interactions between host plant APN1 and rhizobial factors are required, although the biological function of APN1 in nodules and the mechanisms governing the interactions are unknown. To clarify how rhizobial factors are involved in strain-specific nitrogen fixation, we explored transposon mutants of Mesorhizobium loti strain TONO, which normally form Fix− nodules on apn1 roots, and identified TONO mutants that formed Fix+ nodules on apn1. The identified causal gene encodes an autotransporter, part of a protein secretion system of Gram-negative bacteria. Expression of the autotransporter gene in M. loti strain MAFF3030399, which normally forms Fix+ nodules on apn1 roots, resulted in Fix− nodules. The autotransporter of TONO functions to secrete a part of its own protein (a passenger domain) into extracellular spaces, and the recombinant APN1 protein cleaved the passenger protein in vitro. The M. loti autotransporter showed the activity to induce the genes involved in nodule senescence in a dose-dependent manner. Therefore, we conclude that the nodule-specific aspartic peptidase, APN1, suppresses negative effects of the rhizobial autotransporter in order to maintain effective symbiotic nitrogen fixation in root nodules.

scholarly journals FrankiaDiversity in Host Plant Root Nodules Is Independent of Abundance or Relative Diversity ofFrankiaPopulations in Corresponding Rhizosphere Soils

2017 ◽  
Vol 84 (5) ◽  
Author(s):  
Seifeddine Ben Tekaya ◽  
Trina Guerra ◽  
David Rodriguez ◽  
Jeffrey O. Dawson ◽  
Dittmar Hahn
Keyword(s):  
Host Plant ◽  
Root Nodule ◽  
Root Nodules ◽  
Actinorhizal Plants ◽  
Nodule Formation ◽  
Nitrogen Fixing ◽  
Content Type ◽  
Rhizosphere Soils ◽  
Root Nodule Formation ◽  
Host Infection

ABSTRACTActinorhizal plants form nitrogen-fixing root nodules in symbiosis with soil-dwelling actinobacteria within the genusFrankia, and specificFrankiataxonomic clusters nodulate plants in corresponding host infection groups. In same-soil microcosms, we observed that some host species were nodulated (Alnus glutinosa,Alnus cordata,Shepherdia argentea,Casuarina equisetifolia) while others were not (Alnus viridis,Hippophaë rhamnoides). Nodule populations were represented by eight different sequences ofnifHgene fragments. Two of these sequences characterized frankiae inS. argenteanodules, and three others characterized frankiae inA. glutinosanodules. Frankiae inA. cordatanodules were represented by five sequences, one of which was also found in nodules fromA. glutinosaandC. equisetifolia, while another was detected in nodules fromA. glutinosa. Quantitative PCR assays showed that vegetation generally increased the abundance of frankiae in soil, independently of the target gene (i.e.,nifHor the 23S rRNA gene). Targeted Illumina sequencing ofFrankia-specificnifHgene fragments detected 24 unique sequences from rhizosphere soils, 4 of which were also found in nodules, while the remaining 4 sequences in nodules were not found in soils. Seven of the 24 sequences from soils represented >90% of the reads obtained in most samples; the 2 most abundant sequences from soils were not found in root nodules, and only 2 of the sequences from soils were detected in nodules. These results demonstrate large differences between detectableFrankiapopulations in soil and those in root nodules, suggesting that root nodule formation is not a function of the abundance or relative diversity of specificFrankiapopulations in soils.IMPORTANCEThe nitrogen-fixing actinobacteriumFrankiaforms root nodules on actinorhizal plants, with members of specificFrankiataxonomic clusters nodulating plants in corresponding host infection groups. We assessedFrankiadiversity in root nodules of different host plant species, and we related specific populations to the abundance and relative distribution of indigenous frankiae in rhizosphere soils. Large differences were observed between detectableFrankiapopulations in soil and those in root nodules, suggesting that root nodule formation is not a function of the abundance or relative diversity of specificFrankiapopulations in soils but rather results from plants potentially selecting frankiae from the soil for root nodule formation. These data also highlight the necessity of using a combination of different assessment tools so as to adequately address methodological constraints that could produce contradictory data sets.

Histological studies of ectomycorrhizae and root nodules from Cercocarpus montanus and Cercocarpus paucidentatus

1971 ◽  
Vol 49 (8) ◽  
pp. 1315-1318 ◽  
Author(s):  
R. E. Hoeppel ◽  
A. G. Wollum II
Keyword(s):  
Host Plant ◽  
Developmental Stages ◽  
Root Nodules ◽  
Lateral Roots ◽  
Growth Chamber ◽  
Cortical Tissue ◽  
Histological Studies ◽  
Histological Sections ◽  
Mature Nodule ◽  
In Cells

The ectomycorrhizae of Cercocarpus montanus Raf. and Cercocarpus paucidentatus Britt. displayed morphologies ranging from single swollen short lateral roots on long roots to terminal pyramidal clusters. Most short roots appeared to be mycorrhizal, although C. paucidentatus was only infected under growth chamber conditions. Histological sections revealed a conspicuous fungal mantle, averaging 30 μ in thickness, and a Hartig's net.The root nodules appeared as swellings on lateral roots, and later formed compact coralloid orange-colored masses several centimeters in diameter. Histological analyses indicated that both species of Cercocarpus harbored a similar endophyte. Three developmental stages were noted in cortical tissue, including (a) hyphal masses in apical nodule cells; (b) hyphae terminating in 3 × 4 μ club-shaped vesicular swellings; and (c) older structureless hyphal masses in cells of mature nodule branches. The older hyphal masses did not appear to be absorbed by the host plant. The endophyte possessed branching filaments 0.5 μ in diameter and was considered to be an actinomycete.

scholarly journals The Endosymbiosis-Induced Genes ENOD40 and CCS52a Are Involved in Endoparasitic-Nematode Interactions in Medicago truncatula

2002 ◽  
Vol 15 (10) ◽  
pp. 1008-1013 ◽  
Author(s):  
Bruno Favery ◽  
Arnaud Complainville ◽  
Jose Maria Vinardell ◽  
Philippe Lecomte ◽  
Daniàle Vaubert ◽  
...  
Keyword(s):  
Host Plant ◽  
Medicago Truncatula ◽  
Root Nodules ◽  
Expression Patterns ◽  
Cyclin D3 ◽  
Nodule Development ◽  
Cell Cycle Gene ◽  
Root Knot Nematode ◽  
Regulatory Pathways ◽  
Wide Range

Plants associate with a wide range of mutualistic and parasitic biotrophic organisms. Here, we investigated whether beneficial plant symbionts and biotrophic pathogens induce distinct or overlapping regulatory pathways in Medicago truncatula. The symbiosis between Sinorhizobium meliloti and this plant results in the formation of nitrogen-fixing root nodules requiring the activation of specific genes in the host plant. We studied expression patterns of nodule-expressed genes after infection with the root-knot nematode Meloidogyne incognita. Two regulators induced during nodule organogenesis, the early nodulin gene ENOD40 involved in primordium formation and the cell cycle gene CCS52a required for cell differentiation and en-doreduplication, are expressed in galls of the host plant. Expression analysis of promoter-uidA fusions indicates an accumulation of CCS52a transcripts in giant cells undergoing endoreduplication, while ENOD40 expression is localized in surrounding cell layers. Transgenic plants overexpressing ENOD40 show a significantly higher number of galls. In addition, out of the 192 nodule-expressed genes tested, 38 genes were upregulated in nodules at least threefold compared with control roots, but only two genes, nodulin 26 and cyclin D3, were found to be induced in galls. Taken together, these results suggest that certain events, such as endoreduplication, cell-to-cell communication with vascular tissues, or water transport, might be common between giant cell formation and nodule development.

Coproporphyria excretion by Rhizobium meliloti

1969 ◽  
Vol 15 (2) ◽  
pp. 242-244 ◽  
Author(s):  
G. S. Hendry ◽  
D. C. Jordan
Keyword(s):  
Host Plant ◽  
Growth Medium ◽  
Rhizobium Meliloti ◽  
Root Nodules ◽  
Nitrogen Fixing ◽  
Active Nitrogen ◽  
Leguminous Host

Strains of Rhizobium meliloti were found to excrete coproporphyrin into the growth medium. Maximum excretion in a modified Dudman's medium containing arginine occurred at a shaker speed of at least 98 oscillations/min (2 in. travel) and at Fe3+ and biotin concentrations of 1 μg/ml and 1 μg/l respectively. No consistent differences in coproporphyrin excretion were noted among strains differing in their ability to form active, nitrogen-fixing root nodules on their leguminous host plant.

Distribution and abundance of infective, soilborne Frankia and host symbionts Shepherdia, Alnus, and Myrica in a sand dune ecosystem

2004 ◽  
Vol 82 (5) ◽  
pp. 700-709 ◽  
Author(s):  
Janet McCray Batzli ◽  
Jeff F Zimpfer ◽  
Valérie Huguet ◽  
Charles A Smyth ◽  
Maria Fernandez ◽  
...  
Keyword(s):  
Host Plant ◽  
Sand Dune ◽  
Lake Michigan ◽  
Root Nodules ◽  
Vegetative Cover ◽  
Dune System ◽  
Successional Stage ◽  
Greenhouse Study ◽  
Submerged Soils ◽  
Speckled Alder

We describe presence, abundance, and distribution of three sympatric nitrogen-fixing shrubs and their symbiotic diazatroph, Frankia, in a sand dune ecosystem differing in successional stage, vegetative cover, edaphic characteristics, and topography. Distribution of actinorhizal Myrica gale L., Alnus incana (L.) Moench subsp. rugosa (Du Roi) Clausen, and Shepherdia canadensis (L.) Nutt. was analyzed among 120 sampling locations representing a gradient of successional stages in a sand dune system along Lake Michigan. In a greenhouse study, seedlings of these species were employed to bioassay the presence and abundance of infective Frankia in soils. Shepherdia-infective Frankia was detected in 80% of the plots, while Alnus- and Myrica-infective Frankia were found in 65% and 64% of the plots, respectively, with no Frankia found in 18% of the plots. Only 14% of the plots supported actinorhizal host-plant species. Infective Frankia were present in soils of young dunes prior to the establishment of any actinorhizal hosts. Shepherdia-infective Frankia were more abundant in soils from drier, earlier successional sites, while Alnus- and Myrica-infective Frankia were more abundant in moister soils of later successional communities. A previous study had revealed that nodular Frankia strains at this site were host specific for Shepherdia and largely so for Myrica and Alnus, which had only a small proportion of shared strains (Huguet et al. 2001). The likelihood of host-plant nodulation by soilborne Frankia was increased by the presence of actinorhizal plants in general, but not by the presence of their respective specific host plants. Submerged soils had no infectious capacity, whereas soils with greater in situ moisture content and soils subject to intermittent saturation tended to have lower infectious capacities overall. Our results suggest that soilborne, infective Frankia genotypes are not only host specific, but are also associated with spatially and chronologically distinct sets of ecological conditions.Key words: speckled alder, sweet gale, Canada buffalo berry, actinorhizal, nitrogen fixation, Frankia, root nodules.

scholarly journals Metabolite Profiles of Nodulated Alfalfa Plants Indicate That Distinct Stages of Nodule Organogenesis Are Accompanied by Global Physiological Adaptations

2006 ◽  
Vol 19 (9) ◽  
pp. 998-1013 ◽  
Author(s):  
Aiko Barsch ◽  
Verena Tellström ◽  
Thomas Patschkowski ◽  
Helge Küster ◽  
Karsten Niehaus
Keyword(s):  
Organic Acid ◽  
Host Plant ◽  
Developmental Stages ◽  
Root Nodules ◽  
Nitrogen Deficiency ◽  
Metabolic Changes ◽  
Nodule Formation ◽  
Control Mechanisms ◽  
Symbiotic Interaction ◽  
Metabolite Profiles

An effective symbiosis between Sinorhizobium meliloti and its host plant Medicago sativa is dependent on a balanced physiological interaction enabling the microsymbiont to fix atmospheric nitrogen. Maintenance of the symbiotic interaction is regulated by still poorly understood control mechanisms. A first step toward a better understanding of nodule metabolism was the determination of characteristic metabolites for alfalfa root nodules. Furthermore, nodules arrested at different developmental stages were analyzed in order to address metabolic changes induced during the progression of nodule formation. Metabolite profiles of bacteroid-free pseudonodule extracts indicated that early nodule developmental processes are accompanied by photosynthate translocation but no massive organic acid formation. To determine metabolic adaptations induced by the presence of nonfixing bacteroids, nodules induced by mutant S. meliloti strains lacking the nitrogenase protein were analyzed. The bacteroids are unable to provide ammonium to the host plant, which is metabolically reflected by reduced levels of characteristic amino acids involved in ammonium fixation. Elevated levels of starch and sugars in Fix¯ nodules provide strong evidence that plant sanctions preventing a transformation from a symbiotic to a potentially parasitic interaction are not strictly realized via photo-synthate supply. Instead, metabolic and gene expression data indicate that alfalfa plants react to nitrogen-fixation-deficient bacteroids with a decreased organic acid synthesis and an early induction of senescence. Noneffective symbiotic interactions resulting from plants nodulated by mutant rhizobia also are reflected in characteristic metabolic changes in leaves. These are typical for nitrogen deficiency, but also highlight metabolites potentially involved in sensing the N status.

scholarly journals Determinants of Host Range Specificity in Legume-Rhizobia Symbiosis

2020 ◽  
Vol 11 ◽  
Author(s):  
Liam Walker ◽  
Beatriz Lagunas ◽  
Miriam L. Gifford
Keyword(s):  
Host Range ◽  
Host Plant ◽  
Molecular Mechanisms ◽  
High Efficiency ◽  
Current Knowledge ◽  
Root Nodules ◽  
Partner Choice ◽  
Nodule Development ◽  
Symbiotic Association ◽  
Nitrogen Fixing

Leguminous plants possess the almost unique ability to enter symbiosis with soil-resident, nitrogen fixing bacteria called rhizobia. During this symbiosis, the bacteria physically colonize specialized organs on the roots of the host plant called nodules, where they reduce atmospheric nitrogen into forms that can be assimilated by the host plant and receive photosynthates in return. In order for nodule development to occur, there is extensive chemical cross-talk between both parties during the formative stages of the symbiosis. The vast majority of the legume family are capable of forming root nodules and typically rhizobia are only able to fix nitrogen within the context of this symbiotic association. However, many legume species only enter productive symbiosis with a few, or even single rhizobial species or strains, and vice-versa. Permitting symbiosis with only rhizobial strains that will be able to fix nitrogen with high efficiency is a crucial strategy for the host plant to prevent cheating by rhizobia. This selectivity is enforced at all stages of the symbiosis, with partner choice beginning during the initial communication between the plant and rhizobia. However, it can also be influenced even once nitrogen-fixing nodules have developed on the root. This review sets out current knowledge about the molecular mechanisms employed by both parties to influence host range during legume-rhizobia symbiosis.

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