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.

Quantifying the growth of arbuscular mycorrhizal fungi: usefulness of the fractal dimension

Botany ◽  
2009 ◽  
Vol 87 (4) ◽  
pp. 387-400 ◽  
Author(s):  
Christine Juge ◽  
Annie Champagne ◽  
Andrew P. Coughlan ◽  
Nicolas Juge ◽  
Lael Parrott ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Mycorrhizal Fungi ◽  
Growth And Development ◽  
Time Course ◽  
Glomus Intraradices ◽  
Fungal Growth ◽  
Arbuscular Mycorrhizal ◽  
Hyphal Growth ◽  
Growth Cycle

The present study is, to the best of our knowledge, the first to investigate the use of the fractal dimension (FD) to quantify the growth and development of undisturbed, fully functional arbuscular mycorrhizal (AM) hyphae developing in vitro. The majority of the work focused on the model AM fungus Glomus intraradices DAOM 181602. The time course study and final measurements of an intact mature extraradical mycelium allowed us to compare the development of the mycelium and the FD value. The final FD value of 1.62 for the mature mycelium is similar to that obtained for highly branched root systems and tree crowns. The FD method was used to characterize the morphology of germinative and presymbiotic hyphae in the presence of stimulatory (strigolactone GR-24, 0.1 µmol·L–1 and bisphenol A, 10 µmol·L–1) and inhibitory (NaCl, 80 mmol·L–1) molecules, and the extraradical phase in the presence of an inhibitory molecule (NaCl, 80 mmol·L–1). Where possible, results were compared with those obtained using the traditional grid-line (GL) technique. The FD approach allowed treatment effects to be accurately quantified, both in germinative and extraradical phases. In the second case, this technique provided a single quantitative value of extraradical hyphal growth that included runner hyphae (RH) networks, and fine-branching (FB) ramifications. This is in contrast to the GL technique, which provides a value for the estimation of RH, but which is not suitable for accurately measuring FB hyphae. Given the ease with which the FD values can be calculated, and the fact that this method can provide a single value for the quantification of extraradical hyphal growth and development, we suggest that this method is useful for in vitro studies. Furthermore under certain situations of germinative or presymbiotic growth, it may be used in concert with the GL method to provide a greater degree of information about hyphal morphology. The usefulness and limits of the FD method at different stages of the AM fungal growth cycle are discussed.

scholarly journals Identification of a cDNA from the Arbuscular Mycorrhizal Fungus Glomus intraradices that is Expressed During Mycorrhizal Symbiosis and Up-Regulated by N Fertilization

2002 ◽  
Vol 15 (4) ◽  
pp. 360-367 ◽  
Author(s):  
Juan M. Ruiz-Lozano ◽  
Carlos Collados ◽  
Rosa Porcel ◽  
Rosario Azcón ◽  
JoséM. Barea
Keyword(s):  
Gene Expression ◽  
Gene Product ◽  
Time Course ◽  
Glomus Intraradices ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
N Fertilization ◽  
Mycorrhizal Symbiosis ◽  
Transcript Accumulation ◽  
Reading Frame

A cDNA library was constructed with RNA from Glomus intraradices-colonized lettuce roots and used for differential screening. This allowed the identification of a cDNA (Gi-1) that was expressed only in mycorrhizal roots and was of fungal origin. The function of the gene product is unknown, because Gi-1 contained a complete open reading frame that was predicted to encode a protein of 157 amino acids which only showed little homology with glutamine synthetase from Helicobacter pylori. The time-course analysis of gene expression during the fungal life cycle showed that Gi-1 was expressed only during the mycorrhizal symbiosis and was not detected in dormant or germinating spores of G. intraradices. P fertilization did not significantly change the pattern of Gi-1 expression compared with that in the unfertilized treatment, whereas N fertilization (alone or in combination with P) considerably enhanced the Gi-1 transcript accumulation. This increase in gene expression correlated with plant N status and growth under such conditions. The possible role of the Gi-1 gene product in intermediary N metabolism of arbuscular mycorrhizal symbiosis is further discussed.

scholarly journals Reduced Latency in the Metastatic Niche Contributes to the More Aggressive Phenotype of LM8 Compared to Dunn Osteosarcoma Cells

Sarcoma ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Matthias J. E. Arlt ◽  
Ingo J. Banke ◽  
Josefine Bertz ◽  
Ram Mohan Ram Kumar ◽  
Roman Muff ◽  
...  
Keyword(s):  
Time Course ◽  
Kidney Tissue ◽  
Experimental System ◽  
Osteosarcoma Cells ◽  
Primary Tumors ◽  
Liver And Kidney ◽  
Time Course Study ◽  
Cell Dormancy

Metastasis is the major cause of death of osteosarcoma patients and its diagnosis remains difficult. In preclinical studies, however, forced expression of reporter genes in osteosarcoma cells has remarkably improved the detection of micrometastases and, consequently, the quality of the studies. We recently showed that Dunn cells equipped with alacZreporter gene disseminated from subcutaneous primary tumors as frequently as their highly metastatic subline LM8, but only LM8 cells grew to macrometastases. In the present time-course study, tail-vein-injected Dunn and LM8 cells settled within 24 h at the same frequency in the lung, liver, and kidney of mice. Furthermore, Dunn cells also grew to macrometastases, but, compared to LM8, with a delay of two weeks in lung and one week in liver and kidney tissue, consistent with prolonged survival of the mice. Dunn- and LM8-cell-derived ovary and spine metastases occurred less frequently.In vitro, Dunn cells showed less invasiveness and stronger contact inhibition and intercellular adhesion than LM8 cells and several cancer- and dormancy-related genes were differentially expressed. In conclusion, Dunn cells, compared to LM8, have a similar capability but a longer latency to form macrometastases and provide an interesting new experimental system to study tumor cell dormancy.

Nitrogen transfer and assimilation between the arbuscular mycorrhizal fungus Glomus intraradices Schenck & Smith and Ri T-DNA roots of Daucus carota L. in an in vitro compartmented system

2004 ◽  
Vol 50 (4) ◽  
pp. 251-260 ◽  
Author(s):  
Jean-Patrick Toussaint ◽  
Marc St-Arnaud ◽  
Christiane Charest
Keyword(s):  
Glutamine Synthetase ◽  
Daucus Carota ◽  
Glomus Intraradices ◽  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Extraradical Mycelium ◽  
Daucus Carota L ◽  
Hyphal Compartment

Nitrogen metabolism was examined in monoxenic cultures of carrot roots (Daucus carota L.) colonized with the arbuscular mycorrhizal (AM) fungus Glomus intraradices Schenck & Smith. Glutamine synthetase and glutamate dehydrogenase activities were significantly increased in mycorrhizal roots for which only the extraradical mycelium had exclusive access to NH4NO3 in a distinct hyphal compartment inaccessible to the roots. This was in comparison with the water controls but was similar to the enzyme activities of non-arbuscular-mycorrhizal (non-AM) roots that had direct access to NH4NO3. In addition, glutamate dehydrogenase activity was significantly enhanced in AM roots compared with non-AM roots. Carrot roots took up 15NH4+ more efficiently than 15NO3–, and the extraradical hyphae transfered 15NH4+ to host roots from the hyphal compartment but did not transfer 15NO3–. The extraradical mycelium was shown, for the first time, to have a different glutamine synthetase monomer than roots. Our overall results highlight the active role of AM fungi in nitrogen uptake, transfer, and assimilation in their symbiotic root association.Key words: arbuscular mycorrhizal fungus, Ri T-DNA carrot roots, in vitro root-organ culture, nitrogen metabolism.

scholarly journals Establishing monoxenic culture of arbuscular mycorrhizal fungus Glomus intraradices through root organ culture

2014 ◽  
Vol 6 (1) ◽  
pp. 290-293 ◽  
Author(s):  
M. Srinivasan ◽  
K. Kumar ◽  
K. Kumutha ◽  
P. Marimuthu
Keyword(s):  
Hairy Root ◽  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Petri Dish ◽  
Monoxenic Culture ◽  
Surface Sterilization ◽  
Traditional System

Arbuscular mycorrhizal fungi are soil fungi distributed worldwide, forming symbiosis with most of the vascular plants for their growth and survival, which is used for sustainable agriculture and ecosystem management. This study investigated the establishment of monoxenic cultures of Glomus intraradices in association with transformed carrot hairy root. The G.intraradices spores were isolated from sugarcane rhizosphere by wet sieving and decanting technique and propagated in open pot culture. Transformation in to carrot hairy root was done using Agrobacterium rhizogenes. Surface sterilization of G.intraradices spores co-cultured with transformed carrot hairy root in Modified Strulla and Romand (MSR) medium was found the host root growth as well as for germination AM spores. After three months of incubation in dark condition, significant production of extensive hyphal growth on MSR medium and an average of 8500-9000 spores per petri dish was observed. The in vitro inoculum exhibited higher potential of root colonization due to numerous intraradices mycelium with extensive spore load. The produced monoxenic inoculum can be used in place of traditional system where it has a advantage of producing contaminant free propagulas. Thus the monoxenic culture system, a powerful tool, of AM sporulation, can be used for the mass production of monoxenic inoculum of AM fungi besides studying its biology.

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