scholarly journals Nodule Inception Is Not Required for Arbuscular Mycorrhizal Colonization of Medicago truncatula

Plants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 71
Author(s):  
Anil Kumar ◽  
Donna R. Cousins ◽  
Cheng-Wu Liu ◽  
Ping Xu ◽  
Jeremy D. Murray
Keyword(s):  
Arbuscular Mycorrhiza ◽  
Medicago Truncatula ◽  
Time Course ◽  
Phylogenetic Analyses ◽  
Arbuscular Mycorrhizal ◽  
Land Plants ◽  
Altered Expression ◽  
Mycorrhiza Formation ◽  
Mycorrhizal Roots ◽  
Time Course Study

Most legumes can engage in symbiosis with N-fixing bacteria called rhizobia. This symbiosis, called nodulation, evolved from the more widespread symbiosis that most land plants form with arbuscular mycorrhiza, which is reflected in a common requirement of certain genes for both these symbioses. One key nodulation gene, Nodule Inception (NIN), has been intensively studied. Mutants in NIN are unable to form nodules, which has made it difficult to identify downstream genes under the control of NIN. The analysis of data from our recent transcriptomics study revealed that some genes with an altered expression of nin during nodulation are upregulated in mycorrhizal roots. In addition, another study reported the decreased colonization of nin roots by arbuscular mycorrhiza. We therefore investigated a role for NIN in mycorrhiza formation. Our time course study, using two nin alleles with differing genetic backgrounds, suggests that that loss of NIN does not affect colonization of Medicago truncatula roots, either in the presence or absence of rhizobia. This, and recent phylogenetic analyses showing that the loss of NIN is correlated with loss of nodulation in the FaFaCuRo clade, but not with the ability to form mycorrhiza, argue against NIN being required for arbuscular mycorrhization in legumes.

scholarly journals Lipid metabolism in arbuscular mycorrhizal roots of Medicago truncatula

2005 ◽  
Vol 66 (7) ◽  
pp. 781-791 ◽  
Author(s):  
Michael Stumpe ◽  
Jan-Gerrit Carsjens ◽  
Irene Stenzel ◽  
Cornelia Göbel ◽  
Imke Lang ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Medicago Truncatula ◽  
Arbuscular Mycorrhizal ◽  
Mycorrhizal Roots

scholarly journals Investigation of Indigenous Arbuscular Mycorrhizal Performance Using a Lotus japonicus Mycorrhizal Mutant

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 658
Author(s):  
Taisuke Teranishi ◽  
Yoshihro Kobae
Keyword(s):  
Plant Growth ◽  
Arbuscular Mycorrhiza ◽  
Host Plants ◽  
Lotus Japonicus ◽  
Soil Management ◽  
Arbuscular Mycorrhizal ◽  
Mineral Nutrients ◽  
Wild Type ◽  
Arbuscular Mycorrhiza Fungi ◽  
Mycorrhizal Roots

Most plants are usually colonized with arbuscular mycorrhiza fungi (AMF) in the fields. AMF absorb mineral nutrients, especially phosphate, from the soil and transfer them to the host plants. Inoculation with exotic AMF is thought to be effective when indigenous AMF performance is low; however, there is no method for evaluating the performance of indigenous AMF. In this study, we developed a method to investigate the performance of indigenous AMF in promoting plant growth. As Lotus japonicus mutant (str) that are unable to form functional mycorrhizal roots were considered to be symbiosis negative for indigenous mycorrhizal performance, we examined the growth ratios of wild-type and str mycorrhizal mutant using 24 soils. Each soil had its own unique indigenous mycorrhizal performance, which was not directly related to the colonization level of indigenous AMF or soil phosphate level. The low indigenous mycorrhizal performance could not be compensated by the inoculation of exotic AMF. Importantly, indigenous mycorrhizal performance was never negative; however, the inoculation of exotic AMF into the same soil led to both positive and negative performances. These results suggest that indigenous mycorrhizal performance is affected by soil management history and is basically harmless to the plant.

Glomus achrumandG. bistratum,two new species of arbuscular mycorrhizal fungi (Glomeromycota) found in maritime sand dunes

Botany ◽  
2009 ◽  
Vol 87 (3) ◽  
pp. 260-271 ◽  
Author(s):  
Janusz Błaszkowski ◽  
Przemysław Ryszka ◽  
Fritz Oehl ◽  
Sally Koegel ◽  
Andres Wiemken ◽  
...  
Keyword(s):  
Arbuscular Mycorrhiza ◽  
Mycorrhizal Fungi ◽  
Phylogenetic Analyses ◽  
Plantago Lanceolata ◽  
Sand Dunes ◽  
Arbuscular Mycorrhizal ◽  
Its Region ◽  
Ammophila Arenaria ◽  
Vesicular Arbuscular Mycorrhiza ◽  
Vesicular Arbuscular

Two new arbuscular mycorrhizal fungal species, Glomus achrum sp. nov. and Glomus bistratum sp. nov. (Glomeromycota), are described and illustrated. Both species produce small, hyaline spores in aggregates formed in the soil and inside roots. Glomus achrum was associated with roots of Ammophila arenaria (L.) Link colonizing maritime dunes of the Vistula Bar in northern Poland, and G. bistratum occurred among vesicular-arbuscular mycorrhiza of Xanthium cf. spinosum growing in dunes of the Mediterranean Sea adjacent to Veriko, Greece. Spores of G. achrum are globose to subglobose, (25–)43(–55) µm in diameter, rarely egg-shaped, oblong to irregular, 15–45 µm × 55–65 µm. Their wall consists of three hyaline layers: a mucilaginous, short-lived outermost layer; a laminate middle layer composed of loose sublayers; and a flexible innermost layer. The outermost and the innermost layers stain deeply red in Melzer’s reagent. Spores of G. bistratum are globose to subglobose, (20–)29(–50) µm in diameter, and have a wall composed of two permanent, hyaline layers. The outer layer is unit, smooth, and the inner one laminate. Only the inner layer stains yellow in Melzer’s reagent. Both species formed vesicular-arbuscular mycorrhiza in single-species cultures with Plantago lanceolata  L. as the host plant. Phylogenetic analyses of partial 18S rDNA subunit and internal transcribed spacer (ITS) region sequences placed G. achrum and G. bistratum into Glomus group A, but did not reveal any closely related described species. Environmental sequences from the public databases suggested that G. achrum occurred in at least two other plant species from geographically distant regions. No such evidence could be obtained for G. bistratum, which is currently known only from the type location.

scholarly journals Transcription of Two Blue Copper-Binding Protein Isogenes Is Highly Correlated with Arbuscular Mycorrhizal Development in Medicago truncatula

2010 ◽  
Vol 23 (9) ◽  
pp. 1175-1183 ◽  
Author(s):  
István Parádi ◽  
Diederik van Tuinen ◽  
Dominique Morandi ◽  
Sergio Ochatt ◽  
Franck Robert ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Time Course ◽  
Binding Protein ◽  
Quantitative Polymerase Chain Reaction ◽  
Arbuscular Mycorrhizal ◽  
Copper Binding ◽  
Wild Type ◽  
Blue Copper ◽  
Copper Binding Protein ◽  
Mycorrhizal Development

Expression profiling of two paralogous arbuscular mycorrhizal (AM)-specific blue copper-binding gene (MtBcp1a and MtBcp1b) isoforms was performed by real-time quantitative polymerase chain reaction in wild-type Medicago truncatula Jemalong 5 (J5) during the mycorrhizal development with Glomus intraradices for up to 7 weeks. Time-course analysis in J5 showed that expression of both MtBcp1 genes increased continuously and correlated strongly with the colonization intensity and arbuscule content. MtPT4, selected as a reference gene of the functional plant-fungus association, showed a weaker correlation to mycorrhizal development. In a second experiment, a range of mycorrhizal mutants of the wild-type J5 was assessed. Strictly AM-penetration-defective TRV25-C and TRV25-D (dmi3, Mtsym13), hypomycorrhizal TR25 and TR89 (dmi2, Mtsym2) mutants, and a hypermycorrhizal mutant TRV17 (sunn, Mtsym12) were compared with J5 3 and 7 weeks after inoculation. No MtBcp1 transcripts were detected in the mutants blocked at the appressoria stage. Conversely, TR25, TR89, and J5 showed a gradual increase of the expression of both MtBcp1 genes in 3- and 7-week-old plants, similar to the increase in colonization intensity and arbuscule abundance. The strong correlation between the expression level of AM-specific blue copper-binding protein-encoding genes and AM colonization may imply a basic role in symbiotic functioning for these genes, which may serve as new molecular markers of arbuscule development in M. truncatula.

scholarly journals Cloning of putative ureG genes from Glomus intraradices and urease activities in tobacco arbuscular mycorrhizal roots

2009 ◽  
Vol 66 (2) ◽  
pp. 258-266 ◽  
Author(s):  
Daniele Takahashi ◽  
Renata Fava Ditt ◽  
Marcio R. Lambais
Keyword(s):  
Arbuscular Mycorrhizae ◽  
Glomus Intraradices ◽  
Phylogenetic Analyses ◽  
Arbuscular Mycorrhizal ◽  
N Availability ◽  
Mycorrhizal Roots ◽  
Steady State Levels ◽  
N Metabolism ◽  
Activity Of Enzymes ◽  
Tobacco Roots

Even though the major benefit of arbuscular mycorrhizae is the increased uptake of phosphate from the soil solution and translocation to the plant, changes in the activity of enzymes involved in nitrogen (N) metabolism have been detected in mycorrhizal roots. Using differential display of reverse-transcripts of tobacco roots not-inoculated or inoculated with Glomus intraradices (Gi), we have cloned two partial cDNAs (NtGi2 and NtGi3). The presence of a conserved CobW/HypB/UreG domain and phylogenetic analyses suggest that NtGi2 and NtGi3 encode isoforms of urease accessory protein G (ureG) highly similar to ureG from fungi. The steady state levels of the putative ureG transcripts were shown to be higher in roots colonized by Gi, as compared to non-mycorrhizal controls. Urease activities were also determined in tobacco roots inoculated with Glomus clarum (Gc) or Gi and grown in substrate containing 50, 100 or 150 mg N kg-1 in the form of ammonium sulfate (N-AMS) or urea (N-URE). Urease activities were shown to be induced in mycorrhizal roots fertilized with 100 mg N-AMS kg-1. In Gc-colonized roots fertilized with N-URE, induction of urease activities was observed at the lowest N concentration. In contrast, at the highest N-URE concentration, suppression of urease activities was observed in Gc and Gi-colonized roots, as compared to non-mycorrhizal controls. Urease activities in roots were modulated by soil N availability and source, and arbuscular mycorrhizal fungal inoculation.

Suitability of Glomus intraradices in vitro produced spores and root segment inoculum for the establishment of a mycorrhizosphere in an experimental microcosm

2001 ◽  
Vol 79 (8) ◽  
pp. 879-885
Author(s):  
M Filion ◽  
M St-Arnaud ◽  
C Guillon ◽  
C Hamel ◽  
S H Jabaji-Hare
Keyword(s):  
Microbial Ecology ◽  
Time Course ◽  
Glomus Intraradices ◽  
Mycorrhizal Fungus ◽  
Experimental System ◽  
Arbuscular Mycorrhizal ◽  
Root Segment ◽  
Soil Conditions ◽  
Time Course Study

Various experimental systems have been developed to study the mycorrhizosphere. In this study, a microcosm experimental system was constructed and optimized to simulate the environments of the mycorrhizosphere: the rhizosphere, the mycosphere, and the bulk soil, using beans (Phaseolus vulgaris L.) as host plants. We investigated, in a time-course study, the effect of axenically in vitro produced spore inoculum and root segment inoculum of the arbuscular mycorrhizal fungus, Glomus intraradices Schenck & Smith, on extraradical mycelium development, rapidity of mycorrhizal colonization, and plant growth under nonsterile soil conditions. Three concentrations of in vitro produced spores and three concentrations of root segment inoculum produced from open pot cultures were used. The two highest concentrations of spores used as inoculum resulted in faster and more abundant colonization than when root segments were used. A significant correlation was obtained between hyphal densities present in the rhizosphere and mycosphere compartments, and the amount of spore inoculum used. The densities of roots in the rhizosphere compartment and hyphae in the rhizosphere and mycosphere compartments were comparable with field-grown plants; thus, the system realistically mimics a natural mycorrhizosphere. The use of the microcosm described in this study, in combination with the in vitro produced spore inoculum of G. intraradices, represents an experimental approach well adapted for studying the microbial ecology of the mycorrhizosphere.Key words: AMF, microbial ecology, inoculum, mycorrhiza, mycorrhizosphere.

scholarly journals Cloning and Characterization of Two Phosphate Transporters from Medicago truncatula Roots: Regulation in Response to Phosphate and to Colonization by Arbuscular Mycorrhizal (AM) Fungi

1998 ◽  
Vol 11 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Henry Liu ◽  
Anthony T. Trieu ◽  
Laura A. Blaylock ◽  
Maria J. Harrison
Keyword(s):  
Medicago Truncatula ◽  
Expression Patterns ◽  
Arbuscular Mycorrhizal ◽  
Phosphate Starvation ◽  
Purple Acid Phosphatase ◽  
Cdna Clones ◽  
Phosphate Transporters ◽  
Transcript Levels ◽  
Mycorrhizal Roots ◽  
Am Fungus

Most vascular plants can acquire phosphate from the environment either directly, via the roots, or indirectly, via a fungal symbiont that invades the cortical cells of the root. Here we have identified two cDNA clones (MtPT1 and MtPT2) encoding phosphate transporters from a mycorrhizal root cDNA library (Medicago truncatula/Glomus versiforme). The cDNAs represent M. truncatula genes and the encoded proteins share identity with high-affinity phosphate transporters from Arabidopsis, potato, yeast, Neurospora crassa, and an arbuscular mycorrhizal (AM) fungus, G. versiforme. The function of the protein encoded by MtPT1 was confirmed by complementation of a yeast phosphate transport mutant (pho84). The Km of the MtPT1 transporter in this system is 192 μM. MtPT1 and MtPT2 transcripts are present in roots and transcript levels increase in response to phosphate starvation. MtPT transcripts were not detected in leaves. Following colonization of the roots by the AM fungus G. versiforme, both MtPT1 and MtPT2 transcript levels decrease significantly. Down-regulation of phosphate starvation-inducible genes in mycorrhizal roots appears to be a common occurrence and a homologue of a phosphate starvation-inducible purple acid phosphatase is also down-regulated in the mycorrhizal roots. The functional characteristics and expression patterns of the MtPT transporters are consistent with a role in the acquisition of phosphate from the environment but suggest that they may not be involved in phosphate uptake at the symbiotic interface in mycorrhizal roots.

scholarly journals Organization and Metabolism of Plastids and Mitochondria in Arbuscular Mycorrhizal Roots of Medicago truncatula

2005 ◽  
Vol 139 (1) ◽  
pp. 329-340 ◽  
Author(s):  
Swanhild Lohse ◽  
Willibald Schliemann ◽  
Christian Ammer ◽  
Joachim Kopka ◽  
Dieter Strack ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Arbuscular Mycorrhizal ◽  
Mycorrhizal Roots
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