Adhesion to hyphal matrix and antifungal activity ofPseudomonasstrains isolated fromTuber borchiiascocarps

2000 ◽  
Vol 46 (3) ◽  
pp. 259-268 ◽  
Author(s):  
C Sbrana ◽  
G Bagnoli ◽  
S Bedini ◽  
C Filippi ◽  
M Giovannetti ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Mycorrhizal Fungus ◽  
Physiological Role ◽  
Fungal Growth ◽  
Arbuscular Mycorrhizal ◽  
Ectomycorrhizal Fungus ◽  
Growth Modulation ◽  
Tuber Borchii ◽  
Pseudomonas Spp ◽  
Fungal Contaminants

Pseudomonas spp. isolates from Tuber borchii ascocarps, known to be able to produce phytoregulatory and biocontrol substances in pure culture, were used to perform studies on their possible physiological role in nature. Antimycotic activity was confirmed against fungal contaminants isolated from the ascocarps, suggesting that populations associated with Tuber borchii fruit bodies may play a role in the maintenance of ascocarp health. Fifty-five percent of strains tested were also able to release metabolites which affected T. borchii mycelial growth and morphogenesis in culture. On the contrary, growth of the arbuscular mycorrhizal fungus Glomus mosseae and the ectomycorrhizal fungus Laccaria bicolor, putative competitors of Tuber for mycorrhizal infection sites on roots, was not influenced by the presence of any bacterial strain. The possibility that these bacteria, which show antifungal activity and fungal growth modulation activities, might be incorporated in the developing ascocarp by means of their preferential adhesion to Tuber mycelium is discussed.Key words: Tuber borchii, associated bacteria, Pseudomonas spp., biocontrol, adhesion.

Tricholoma matsutake fruit bodies secrete hydrogen peroxide as a potent inhibitor of fungal growth

2015 ◽  
Vol 61 (6) ◽  
pp. 447-450 ◽  
Author(s):  
Yoshimitsu Takakura
Keyword(s):  
Hydrogen Peroxide ◽  
Antimicrobial Activity ◽  
Antifungal Activity ◽  
Rhizoctonia Solani ◽  
Microbial Communities ◽  
Potent Inhibitor ◽  
Fungal Growth ◽  
Ectomycorrhizal Fungus ◽  
Tricholoma Matsutake ◽  
Pyranose Oxidase

Tricholoma matsutake is an ectomycorrhizal fungus that dominates the microbial communities in the soil of pine and spruce forests. The mycorrhizas of this fungus have antimicrobial activity, although factors responsible for the antimicrobial activity have not been fully elucidated. The present study shows that fruit bodies of T. matsutake secreted hydrogen peroxide (H2O2), which was produced by pyranose oxidase, and that the H2O2 thus secreted strongly inhibited the growth of mycelia of the phytopathological fungus Rhizoctonia solani. These findings suggest that fruit bodies of T. matsutake have antifungal activity and that the pyranose oxidase plays an important role in the antifungal activity.

scholarly journals Towards Growth of Arbuscular Mycorrhizal Fungi Independent of a Plant Host

2002 ◽  
Vol 68 (4) ◽  
pp. 1919-1924 ◽  
Author(s):  
Ulrich Hildebrandt ◽  
Katharina Janetta ◽  
Hermann Bothe
Keyword(s):  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Mycorrhizal Fungus ◽  
Fungal Growth ◽  
Arbuscular Mycorrhizal ◽  
Plant Host ◽  
Significant Step ◽  
Hyphal Coils ◽  
K 12 ◽  
Root Tissues

ABSTRACT When surface-sterilized spores of the arbuscular mycorrhizal fungus (AMF) Glomus intraradices Sy167 were germinated on agar plates in the slightly modified minimum mineral medium described by G. Bécard and J. A. Fortin (New Phytol. 108:211-218, 1988), slime-forming bacteria, identified as Paenibacillus validus, frequently grew up. These bacteria were able to support growth of the fungus on the agar plates. In the presence of P. validus, hyphae branched profusely and formed coiled structures. These were much more densely packed than the so-called arbuscule-like structures which are formed by AMF grown in coculture with carrot roots transformed with T-DNA from Agrobacterium rhizogenes. The presence of P. validus alone also enabled G. intraradices to form new spores, mainly at the densely packed hyphal coils. The new spores were not as abundant as and were smaller than those formed by AMF in the monoxenic culture with carrot root tissues, but they also contained lipid droplets and a large number of nuclei. In these experiments P. validus could not be replaced by bacteria such as Escherichia coli K-12 or Azospirillum brasilense Sp7. Although no conditions under which the daughter spores regerminate and colonize plants have been found yet, and no factor(s) from P. validus which stimulates fungal growth has been identified, the present findings might be a significant step forward toward growth of AMF independent of any plant host.

Symbiosis of Acacia auriculiformis and Acacia mangium with mycorrhizal fungi and Bradyrhizobium spp. improves salt tolerance in greenhouse conditions

2005 ◽  
Vol 32 (12) ◽  
pp. 1143 ◽  
Author(s):  
Diégane Diouf ◽  
Robin Duponnois ◽  
Amadou Tidiane Ba ◽  
Marc Neyra ◽  
Didier Lesueur
Keyword(s):  
Salt Tolerance ◽  
Mineral Nutrition ◽  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Mycorrhizal Fungus ◽  
Acacia Mangium ◽  
Arbuscular Mycorrhizal ◽  
Ectomycorrhizal Fungus ◽  
Acacia Auriculiformis ◽  
Acacia Species

The aim of our work was to assess the growth and mineral nutrition of salt stressed Acacia auriculiformis A. Cunn. ex Benth. and Acacia mangium Willd. seedlings inoculated with a combination of selected microsymbionts (bradyrhizobia and mycorrhizal fungi). Plants were grown in greenhouse conditions in non-sterile soil, irrigated with a saline nutrient solution (0, 50 and 100 mm NaCl). The inoculation combinations consisted of the Bradyrhizobium strain Aust 13c for A. mangium and Aust 11c for A. auriculiformis, an arbuscular mycorrhizal fungus (Glomus intraradices, DAOM 181602) and an ectomycorrhizal fungus (Pisolithus albus, strain COI 007). The inoculation treatments were designed to identify the symbionts that might improve the salt tolerance of both Acacia species. The main effect of salinity was reduced tree growth in both acacias. However, it appeared that, compared with controls, both rhizobial and mycorrhizal inoculation improved the growth of the salt-stressed plants, while inoculation with the ectomycorrhizal fungus strain appeared to have a small effect on their growth and mineral nutrition levels. Endomycorrhizal inoculation combined with rhizobial inoculation usually gave good results. Analysis of foliar proline accumulation confirmed that dual inoculation gave the trees better tolerance to salt stress and suggested that the use of this dual inoculum might be beneficial for inoculation of both Acacia species in soils with moderate salt constraints.

scholarly journals The ftsZ Gene of the Endocellular Bacterium ‘Candidatus Glomeribacter gigasporarum’ Is Preferentially Expressed During the Symbiotic Phases of Its Host Mycorrhizal Fungus

2009 ◽  
Vol 22 (3) ◽  
pp. 302-310 ◽  
Author(s):  
Iulia-Andra Anca ◽  
Erica Lumini ◽  
Stefano Ghignone ◽  
Alessandra Salvioli ◽  
Valeria Bianciotto ◽  
...  
Keyword(s):  
Positive Impact ◽  
Marker Gene ◽  
Mycorrhizal Fungus ◽  
Fungal Growth ◽  
Arbuscular Mycorrhizal ◽  
Bacterial Gene ◽  
Gene Transcripts ◽  
Polymerase Chain ◽  
Fungal Life Cycle ◽  
Polymerase Chain Reaction Data

The arbuscular mycorrhizal fungus (AM) Gigaspora margarita consistently hosts bacteria, named ‘Candidatus Glomeribacter gigasporarum,’ inside its cytoplasm. Endobacteria have a positive impact on fungal fitness during the presymbiotic phase, prior to plant roots colonization. We tested the hypothesis that the endobacterium and its cell divisions depend on fungal metabolism, mirroring also the events of the fungal life cycle which are influenced by plant signals. We first cloned a fragment of ftsZ, a marker gene for bacterial division, and then analyzed its expression along the different stages of fungus development. The bacterial gene transcripts showed the highest values when the fungus was associated to the plant, and peaked in the extraradical mycelium. Strigolactones, which are known to stimulate the AM fungal growth, caused a significant transcript increase in the germinated spores in the absence of the plant. The quantitative real-time reverse-transcription polymerase chain reaction data were strengthened by the quantification of the dividing bacteria, which were increasing in number in germinating spores after the strigolactone treatment. The bioactive molecule alone did not cause any change in the number of bacteria after their isolation from the fungus, thus showing that the strigolactone alone cannot confer free-living capacities to the bacterium.

scholarly journals Competitive PCR for Quantitation of a Cytophaga-Flexibacter-Bacteroides Phylum Bacterium Associated with the Tuber borchii Vittad. Mycelium

2002 ◽  
Vol 68 (12) ◽  
pp. 6421-6424 ◽  
Author(s):  
Elena Barbieri ◽  
Giulia Riccioni ◽  
Anna Pisano ◽  
Davide Sisti ◽  
Sabrina Zeppa ◽  
...  
Keyword(s):  
16S Rrna ◽  
Mycorrhizal Fungus ◽  
Ectomycorrhizal Fungus ◽  
Rrna Gene ◽  
Competitive Pcr ◽  
Tuber Borchii ◽  
Uncultured Bacterium ◽  
Pcr Targeting ◽  
The 16S Rrna Gene ◽  
Number Of Bacteria

ABSTRACT An uncultured bacterium associated with the ectomycorrhizal fungus Tuber borchii Vittad. was identified as a novel member of the Cytophaga-Flexibacter-Bacteroides group. Utilizing a quantitative PCR targeting the 16S rRNA gene, we relatively quantified this bacterium in the host. The estimated number of bacteria was found to be approximately 106 cells per 30-day-old T. borchii mycelium culture. This represents the first molecular attempt to enumerate an uncultured bacterium associated with a mycorrhizal fungus.

scholarly journals The Exotic Legume Tree Species Acacia holosericea Alters Microbial Soil Functionalities and the Structure of the Arbuscular Mycorrhizal Community

2008 ◽  
Vol 74 (5) ◽  
pp. 1485-1493 ◽  
Author(s):  
P. Remigi ◽  
A. Faye ◽  
A. Kane ◽  
M. Deruaz ◽  
J. Thioulouse ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Tree Species ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Ectomycorrhizal Fungus ◽  
Soil Microbial ◽  
Exotic Tree ◽  
Acacia Holosericea ◽  
Arbuscular Mycorrhizal Community ◽  
Exotic Legume

ABSTRACT The response of microbial functional diversity as well as its resistance to stress or disturbances caused by the introduction of an exotic tree species, Acacia holosericea, ectomycorrhized or not with Pisolithus albus, was examined. The results show that this ectomycorrhizal fungus promotes drastically the growth of this fast-growing tree species in field conditions after 7 years of plantation. Compared to the crop soil surrounding the A. holosericea plantation, this exotic tree species, associated or not with the ectomycorrhizal symbiont, induced strong modifications in soil microbial functionalities (assessed by measuring the patterns of in situ catabolic potential of microbial communities) and reduced soil resistance in response to increasing stress or disturbance (salinity, temperature, and freeze-thaw and wet-dry cycles). In addition, A. holosericea strongly modified the structure of arbuscular mycorrhizal fungus communities. These results show clearly that exotic plants may be responsible for important changes in soil microbiota affecting the structure and functions of microbial communities.

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