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Uroz S, Courty PE, Pierrat JC, Peter M, Buée M, Turpault MP, Garbaye J, Frey-Klett P. Functional profiling and distribution of the forest soil bacterial communities along the soil mycorrhizosphere continuum. Microb Ecol 2013; 66:404-15. [PMID: 23455431 DOI: 10.1007/s00248-013-0199-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 02/08/2013] [Indexed: 05/09/2023]
Abstract
An ectomycorrhiza is a multitrophic association between a tree root, an ectomycorrhizal fungus, free-living fungi and the associated bacterial communities. Enzymatic activities of ectomycorrhizal root tips are therefore result of the contribution from different partners of the symbiotic organ. However, the functional potential of the fungus-associated bacterial communities remains unknown. In this study, a collection of 80 bacterial strains randomly selected and isolated from a soil-ectomycorrhiza continuum (oak-Scleroderma citrinum ectomycorrhizas, the ectomycorrhizosphere and the surrounding bulk soil) were characterized. All the bacterial isolates were identified by partial 16S rRNA gene sequences as members of the genera Burkholderia, Collimonas, Dyella, Mesorhizobium, Pseudomonas, Rhizobium and Sphingomonas. The bacterial strains were then assayed for β-xylosidase, β-glucosidase, N-acetyl-hexosaminidase, β-glucuronidase, cellobiohydrolase, phosphomonoesterase, leucine-aminopeptidase and laccase activities, chitin solubilization and auxin production. Using these bioassays, we demonstrated significant differences in the functional distribution of the bacterial communities living in the different compartments of the soil-ectomycorrhiza continuum. The surrounding bulk soil was significantly enriched in bacterial isolates capable of hydrolysing cellobiose and N-acetylglucosamine. In contrast, the ectomycorrhizosphere appeared significantly enriched in bacterial isolates capable of hydrolysing glucopyranoside and chitin. Notably, chitinase and laccase activities were found only in bacterial isolates belonging to the Collimonas and Pseudomonas genera. Overall, the results suggest that the ectomycorrhizal fungi favour specific bacterial communities with contrasting functional characteristics from the surrounding soil.
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Affiliation(s)
- S Uroz
- INRA, UMR1136 INRA-Nancy Université Interactions Arbres-Microorganismes, Centre INRA de Nancy, 54280, Champenoux, France.
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Courty PE, Labbé J, Kohler A, Marçais B, Bastien C, Churin JL, Garbaye J, Le Tacon F. Effect of poplar genotypes on mycorrhizal infection and secreted enzyme activities in mycorrhizal and non-mycorrhizal roots. J Exp Bot 2011; 62:249-60. [PMID: 20881013 PMCID: PMC2993916 DOI: 10.1093/jxb/erq274] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 07/24/2010] [Accepted: 08/03/2010] [Indexed: 05/10/2023]
Abstract
The impact of ectomycorrhiza formation on the secretion of exoenzymes by the host plant and the symbiont is unknown. Thirty-eight F(1) individuals from an interspecific Populus deltoides (Bartr.)×Populus trichocarpa (Torr. & A. Gray) controlled cross were inoculated with the ectomycorrhizal fungus Laccaria bicolor. The colonization of poplar roots by L. bicolor dramatically modified their ability to secrete enzymes involved in organic matter breakdown or organic phosphorus mobilization, such as N-acetylglucosaminidase, β-glucuronidase, cellobiohydrolase, β-glucosidase, β-xylosidase, laccase, and acid phosphatase. The expression of genes coding for laccase, N-acetylglucosaminidase, and acid phosphatase was studied in mycorrhizal and non-mycorrhizal root tips. Depending on the genes, their expression was regulated upon symbiosis development. Moreover, it appears that poplar laccases or phosphatases contribute poorly to ectomycorrhiza metabolic activity. Enzymes secreted by poplar roots were added to or substituted by enzymes secreted by L. bicolor. The enzymatic activities expressed in mycorrhizal roots differed significantly between the two parents, while it did not differ in non-mycorrhizal roots. Significant differences were found between poplar genotypes for all enzymatic activities measured on ectomycorrhizas except for laccases activity. In contrast, no significant differences were found between poplar genotypes for enzymatic activities of non-mycorrhizal root tips except for acid phosphatase activity. The level of enzymes secreted by the ectomycorrhizal root tips is under the genetic control of the host. Moreover, poplar heterosis was expressed through the enzymatic activities of the fungal partner.
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Affiliation(s)
- P E Courty
- UMR 1136 INRA-Nancy Université, Interactions Arbres/Microorganismes, INRA-Nancy, 54280 Champenoux, France.
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Deveau A, Brulé C, Palin B, Champmartin D, Rubini P, Garbaye J, Sarniguet A, Frey-Klett P. Role of fungal trehalose and bacterial thiamine in the improved survival and growth of the ectomycorrhizal fungus Laccaria bicolor S238N and the helper bacterium Pseudomonas fluorescens BBc6R8. Environ Microbiol Rep 2010; 2:560-568. [PMID: 23766226 DOI: 10.1111/j.1758-2229.2010.00145.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The mycorrhiza helper bacterial strain Pseudomonas fluorescens BBc6R8 enhances the establishment of Laccaria bicolor S238N ectomycorrhizae by improving the pre-symbiotic growth and survival of the fungus. Nothing is known about the effect of the ectomycorrhizal fungus on the helper bacteria or the molecules that are involved in the interaction. In this study, we have monitored the population density of the helper strain P. fluorescens BBc6R8 in soils inoculated with L. bicolor and in control soils and found that the ectomycorhizal fungus improves the survival of the helper bacteria. We investigated the identity of the fungal and bacterial metabolites involved in this reciprocal growth-promoting effect using a combination of growth measurements, chemoattractant assays, HPLC and in silico genome analyses. We showed that trehalose, a disaccharide that accumulates to high levels in the fungal hyphae, chemoattracted and promoted the growth of the helper bacteria. Meanwhile, P. fluorescens BBc6R8 produced thiamine at concentrations that enhanced the fungal growth in vitro. Altogether our data indicate that the interaction between the two microorganisms is beneficial for both species and relies, at least in part, on trophic mutualism.
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Affiliation(s)
- A Deveau
- INRA, UMR1136 INRA-Nancy Université«Interactions Arbres/Micro-organismes», Centre de Nancy, IFR110, 54280 Champenoux, France. SRSMC (Structure et Réactivité des Systèmes Moléculaires Complexes) UMR7565, Université Henri Poincaré- Nancy 1, Nancy-Université, France. INRA, UMR1099 'Biologie des Organismes et des Populations appliquée à la Protection des Plantes', 35 653 Le Rheu Cedex, France
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Frey P, Frey-Klett P, Garbaye J, Berge O, Heulin T. Metabolic and Genotypic Fingerprinting of Fluorescent Pseudomonads Associated with the Douglas Fir-Laccaria bicolor Mycorrhizosphere. Appl Environ Microbiol 2010; 63:1852-60. [PMID: 16535600 PMCID: PMC1389155 DOI: 10.1128/aem.63.5.1852-1860.1997] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A collection of 300 isolates of fluorescent pseudomonads was established from Douglas fir-Laccaria bicolor mycorrhizas and mycorrhizosphere and from adjacent bulk soil. These isolates were first phenotypically characterized with the Biolog method. Taxonomic identification assigned 90% of the isolates to the different biovars of Pseudomonas fluorescens, with inverted frequencies of biovars V and I from the bulk soil to the mycorrhizas, suggesting that the mycorrhizas exert a selective stimulation of the P. fluorescens bv. I and a counterselection of the P. fluorescens bv. V present in the soil. Multivariate analyses of the carbon source utilization data led to the definition of homogenous metabolic groups and to the identification of the most discriminating substrates for each group. The isolates from the mycorrhizosphere and from the mycorrhizas seem to preferentially utilize carbohydrates, in particular trehalose, which is the most abundant carbohydrate accumulated in the mycelium of L. bicolor. The results suggest that L. bicolor exerts a trehalose-mediated selection on the fluorescent pseudomonads present in the vicinity of the mycorrhizas. Isolates of P. fluorescens from the mycorrhizosphere and mycorrhizas were then genotypically characterized by restriction fragment length polymorphism of PCR-amplified 16S rRNA genes and enterobacterial repetitive intergenic consensus-PCR DNA fingerprinting. Both methods revealed a high genetic polymorphism within the population studied, which was well correlated with the phenotypic characterization.
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Frey-Klett P, Pierrat JC, Garbaye J. Location and Survival of Mycorrhiza Helper Pseudomonas fluorescens during Establishment of Ectomycorrhizal Symbiosis between Laccaria bicolor and Douglas Fir. Appl Environ Microbiol 2010; 63:139-44. [PMID: 16535478 PMCID: PMC1389093 DOI: 10.1128/aem.63.1.139-144.1997] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mycorrhiza helper bacterium Pseudomonas fluorescens BBc6, isolated from a Laccaria bicolor sporocarp, consistently promotes L. bicolor-Douglas fir (Pseudotsuga menziesii) ectomycorrhizal formation, even with low doses of bacterial inoculum. In order to describe this phenomenon more accurately, we have looked at the location and survival of the introduced bacterial strain in the soil and in the rhizosphere during the establishment of mycorrhizal symbiosis in glasshouse and nursery experiments. Bacterial populations were quantified with a spontaneous, stable, rifampin-resistant mutant, BBc6R8, which phenotypically conformed to the parental strain. BBc6R8 populations declined rapidly, reaching the detection limit after 19 weeks, and did not increase either when L. bicolor sporocarps were forming in autumn or when Douglas fir roots resumed growing in spring. BBc6R8 was neither an endophyte nor a rhizobacterium. Furthermore, it was not particularly associated with either mycorrhizas of Douglas fir-L. bicolor or L. bicolor sporocarps. Surprisingly, a significant mycorrhiza helper effect was observed when the inoculated BBc6R8 population had dropped as low as 30 CFU g of dry matter(sup-1) in the soil. This study raises questions concerning the bacterial concentration in the soil which is effective for promotion of mycorrhizal establishment and the timing of the bacterial effect. It allows us to develop working hypotheses, which can be tested experimentally, to identify the mechanisms of the mycorrhiza helper effect.
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Courty PE, Hoegger PJ, Kilaru S, Kohler A, Buée M, Garbaye J, Martin F, Kües U. Phylogenetic analysis, genomic organization, and expression analysis of multi-copper oxidases in the ectomycorrhizal basidiomycete Laccaria bicolor. New Phytol 2009; 182:736-750. [PMID: 19243515 DOI: 10.1111/j.1469-8137.2009.02774.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In forest soils, ectomycorrhizal and saprotrophic Agaricales differ in their strategies for carbon acquisition, but share common gene families encoding multi-copper oxidases (MCOs). These enzymes are involved in the oxidation of a variety of soil organic compounds. The MCO gene family of the ectomycorrhizal fungus Laccaria bicolor is composed of 11 genes divided into two distinct subfamilies corresponding to laccases (lcc) sensu stricto (lcc1 to lcc9), sharing a high sequence homology with the coprophilic Coprinopsis cinerea laccase genes, and to ferroxidases (lcc10 and lcc11) that are not present in C. cinerea. The fet3-like ferroxidase genes lcc10 and lcc11 in L. bicolor are each arranged in a mirrored tandem orientation with an ftr gene coding for an iron permease. Unlike C. cinerea, L. bicolor has no sid1/sidA gene for siderophore biosynthesis. Transcript profiling using whole-genome expression arrays and quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) revealed that some transcripts were very abundant in ectomycorrhizas (lcc3 and lcc8), in fruiting bodies (lcc7) or in the free-living mycelium grown on agar medium (lcc9 and lcc10), suggesting a specific function of these MCOs. The amino acid composition of the MCO substrate binding sites suggests that L. bicolor MCOs interact with substrates different from those of saprotrophic fungi.
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Affiliation(s)
- P E Courty
- UMR 1136 INRA-Nancy Université, Interactions Arbres/Microorganisms, INRA-Nancy, 54280 Champenoux, France
- Botanical Institute, University of Basel, CH-4056 Basel, Switzerland
| | - P J Hoegger
- Molecular Wood Biotechnology and Technical Mycology, Büsgen-Institute, Georg-August-University, D-37077 Göttingen, Germany
| | - S Kilaru
- Molecular Wood Biotechnology and Technical Mycology, Büsgen-Institute, Georg-August-University, D-37077 Göttingen, Germany
| | - A Kohler
- UMR 1136 INRA-Nancy Université, Interactions Arbres/Microorganisms, INRA-Nancy, 54280 Champenoux, France
| | - M Buée
- UMR 1136 INRA-Nancy Université, Interactions Arbres/Microorganisms, INRA-Nancy, 54280 Champenoux, France
| | - J Garbaye
- UMR 1136 INRA-Nancy Université, Interactions Arbres/Microorganisms, INRA-Nancy, 54280 Champenoux, France
| | - F Martin
- UMR 1136 INRA-Nancy Université, Interactions Arbres/Microorganisms, INRA-Nancy, 54280 Champenoux, France
| | - U Kües
- Molecular Wood Biotechnology and Technical Mycology, Büsgen-Institute, Georg-August-University, D-37077 Göttingen, Germany
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Courty PE, Poletto M, Duchaussoy F, Buée M, Garbaye J, Martin F. Gene transcription in Lactarius quietus-Quercus petraea ectomycorrhizas from a forest soil. Appl Environ Microbiol 2008; 74:6598-605. [PMID: 18791033 PMCID: PMC2576711 DOI: 10.1128/aem.00584-08] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 08/29/2008] [Indexed: 11/20/2022] Open
Abstract
Extracting fungal mRNA from ectomycorrhizas (ECMs) and forest soil samples for monitoring in situ metabolic activities is a significant challenge when studying the role of ECMs in biogeochemical cycles. A robust, simple, rapid, and effective method was developed for extracting RNA from rhizospheric soil and ECMs by adapting previous grinding and lysis methods. The quality and yield of the extracted RNA were sufficient to be used for reverse transcription. RNA extracted from ECMs of Lactarius quietus in a 100-year-old oak stand was used to construct a cDNA library and sequence expressed sequence tags. The transcripts of many genes involved in primary metabolism and in the degradation of organic matter were found. The transcription levels of four targeted fungal genes (glutamine synthase, a general amino acid transporter, a tyrosinase, and N-acetylhexosaminidase) were measured by quantitative reverse transcription-PCR in ECMs and in the ectomycorrhizospheric soil (the soil surrounding the ECMs containing the extraradical mycelium) in forest samples. On average, levels of gene expression for the L. quietus ECM root tips were similar to those for the extraradical mycelium, although gene expression varied up to 10-fold among the samples. This study demonstrates that gene expression from ECMs and soil can be analyzed. These results provide new perspectives for investigating the role of ectomycorrhizal fungi in the functioning of forest ecosystems.
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Affiliation(s)
- P E Courty
- UMR 1136, INRA-Nancy Université, Interactions Arbres/Microorganismes, INRA-Nancy, 54280 Champenoux, France.
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Kabre A, Garbaye J, le Tacon F. Influence de la mycorhization et de la fertilisation sur le comportement de jeunes plants d'érable sycomore (Acer pseudoplatanus Link.). ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1439-0329.1982.tb01378.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
In natural conditions, mycorrhizal fungi are surrounded by complex microbial communities, which modulate the mycorrhizal symbiosis. Here, the focus is on the so-called mycorrhiza helper bacteria (MHB). This concept is revisited, and the distinction is made between the helper bacteria, which assist mycorrhiza formation, and those that interact positively with the functioning of the symbiosis. After considering some examples of MHB from the literature, the ecological and evolutionary implications of the relationships of MHB with mycorrhizal fungi are discussed. The question of the specificity of the MHB effect is addressed, and an assessment is made of progress in understanding the mechanisms of the MHB effect, which has been made possible through the development of genomics. Finally, clear evidence is presented suggesting that some MHB promote the functioning of the mycorrhizal symbiosis. This is illustrated for three critical functions of practical significance: nutrient mobilization from soil minerals, fixation of atmospheric nitrogen, and protection of plants against root pathogens. The review concludes with discussion of future research priorities regarding the potentially very fruitful concept of MHB.
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Affiliation(s)
- P Frey-Klett
- INRA, UMR1136 INRA-UHP 'Interactions Arbres/Micro-organismes', IFR 110, Centre de Nancy, 54280 Champenoux, France
| | - J Garbaye
- INRA, UMR1136 INRA-UHP 'Interactions Arbres/Micro-organismes', IFR 110, Centre de Nancy, 54280 Champenoux, France
| | - M Tarkka
- UFZ-Department of Soil Ecology, Helmholz Centre for Environmental Research, Theodor-Lieser-Strasse 4, 06120 Halle, Germany
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Deveau A, Palin B, Delaruelle C, Peter M, Kohler A, Pierrat JC, Sarniguet A, Garbaye J, Martin F, Frey-Klett P. The mycorrhiza helper Pseudomonas fluorescens BBc6R8 has a specific priming effect on the growth, morphology and gene expression of the ectomycorrhizal fungus Laccaria bicolor S238N. New Phytol 2007; 175:743-755. [PMID: 17688589 DOI: 10.1111/j.1469-8137.2007.02148.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The mycorrhiza helper Pseudomonas fluorescens BBc6R8 promotes the presymbiotic survival and growth of the ectomycorrhizal fungus Laccaria bicolor S238N in the soil. An in vitro fungal-bacterial confrontation bioassay mimicking the promoting effects of the bacteria on fungal growth was set up to analyse the fungal morphological and transcriptional changes induced by the helper bacteria at three successive stages of the interaction. The specificity of the P. fluorescens BBc6R8 effect was assessed in comparison with six other rhizobacterial strains possessing mycorrhiza helper or pathogen antagonistic abilities. The helper BBc6R8 strain was the only strain to induce increases in the radial growth of the colony, hyphal apex density and branching angle. These morphological modifications were coupled with pleiotropic alterations of the fungal transcriptome, which varied throughout the interaction. Early stage-responsive genes were presumably involved in recognition processes and transcription regulation, while late stage-responsive genes encoded proteins of primary metabolism. Some of the responsive genes were partly specific to the interaction with P. fluorescens BBc6R8, whereas others were mutually regulated by different rhizobacteria. The results highlight the fact that the helper BBc6R8 strain has a specific priming effect on growth, morphology and gene expression of its fungal associate L. bicolor S238N.
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Affiliation(s)
- A Deveau
- INRA, UMR1136 'Interactions Arbres/Micro-organismes', IFR 110 Centre de Nancy, 54280 Champenoux, France
| | - B Palin
- INRA, UMR1136 'Interactions Arbres/Micro-organismes', IFR 110 Centre de Nancy, 54280 Champenoux, France
| | - C Delaruelle
- INRA, UMR1136 'Interactions Arbres/Micro-organismes', IFR 110 Centre de Nancy, 54280 Champenoux, France
| | - M Peter
- INRA, UMR1136 'Interactions Arbres/Micro-organismes', IFR 110 Centre de Nancy, 54280 Champenoux, France
| | - A Kohler
- INRA, UMR1136 'Interactions Arbres/Micro-organismes', IFR 110 Centre de Nancy, 54280 Champenoux, France
| | - J C Pierrat
- INRA-ENGREF, UMR1092, Unité Dynamique des Systèmes Forestiers, 54042 Nancy, France
| | - A Sarniguet
- INRA-Agrocampus Rennes, UMR1099 'Biologie des Organismes et des Populations appliquée à la Protection des Plantes', 35 653 Le Rheu Cedex, France
| | - J Garbaye
- INRA, UMR1136 'Interactions Arbres/Micro-organismes', IFR 110 Centre de Nancy, 54280 Champenoux, France
| | - F Martin
- INRA, UMR1136 'Interactions Arbres/Micro-organismes', IFR 110 Centre de Nancy, 54280 Champenoux, France
| | - P Frey-Klett
- INRA, UMR1136 'Interactions Arbres/Micro-organismes', IFR 110 Centre de Nancy, 54280 Champenoux, France
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Bertaux J, Schmid M, Hutzler P, Hartmann A, Garbaye J, Frey-Klett P. Occurrence and distribution of endobacteria in the plant-associated mycelium of the ectomycorrhizal fungus Laccaria bicolor S238N. Environ Microbiol 2006; 7:1786-95. [PMID: 16232293 DOI: 10.1111/j.1462-2920.2005.00867.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Fluorescence in situ hybridization, associated with confocal laser scanning microscopy or epifluorescence microscopy with deconvolution system, has allowed the detection of a community of intracellular bacteria in non-axenic samples of the ectomycorrhizal fungus Laccaria bicolor S238N. The endobacteria, mainly alpha-proteobacteria, were present in more than half of the samples, which consisted of ectomycorrhizae, fungal mats and fruit bodies, collected in the glasshouse or in the forest. Acridine orange staining suggests that the endobacteria inhabit both live and dead fungal cells. The role of these endobacteria remains to be clarified.
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Affiliation(s)
- J Bertaux
- UMR INRA-UHP Interactions Arbres/Micro-organismes, Centre INRA de Nancy, 54280 Champenoux, France
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Frey-Klett P, Garbaye J. Mycorrhiza helper bacteria: a promising model for the genomic analysis of fungal-bacterial interactions. New Phytol 2005; 168:4-8. [PMID: 16159316 DOI: 10.1111/j.1469-8137.2005.01553.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
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Tagu D, Bastien C, Faivre-Rampant P, Garbaye J, Vion P, Villar M, Martin F. Genetic analysis of phenotypic variation for ectomycorrhiza formation in an interspecific F1 poplar full-sib family. Mycorrhiza 2005; 15:87-91. [PMID: 15015061 DOI: 10.1007/s00572-004-0302-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2003] [Accepted: 02/11/2004] [Indexed: 05/03/2023]
Abstract
A plant's capability to develop ectomycorrhizal symbiosis is under the control of both genetic and environmental factors. In order to determine the roles played by these different factors, we have performed a quantitative genetic analysis of the ability of poplar trees to form ectomycorrhizas. Quantitative genetics were applied to an interspecific family of poplar for which the two parental genetic maps had already been described, and for which data analyses concerning fungal aggressors were obtained. Quantitative trait loci (QTL) related to ectomycorrhiza formation were identified and located in the genetic maps of the two parents. One QTL was located at a linkage group of the genetic map of Populus trichocarpa showing a high concentration of several QTL involved in the pathogenic interaction with the fungus Melampsora larici-populina, the causal agent of leaf rust.
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Affiliation(s)
- D Tagu
- UMR INRA-UHP 1136 IaM Interactions Arbres/Micro-Organismes, INRA, 54280, Champenoux, France.
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Bertaux J, Schmid M, Prevost-Boure NC, Churin JL, Hartmann A, Garbaye J, Frey-Klett P. In situ identification of intracellular bacteria related to Paenibacillus spp. in the mycelium of the ectomycorrhizal fungus Laccaria bicolor S238N. Appl Environ Microbiol 2003; 69:4243-8. [PMID: 12839806 PMCID: PMC165139 DOI: 10.1128/aem.69.7.4243-4248.2003] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2003] [Accepted: 04/30/2003] [Indexed: 11/20/2022] Open
Abstract
Bacterial proliferations have recurrently been observed for the past 15 years in fermentor cultures of the ectomycorrhizal fungus Laccaria bicolor S238N, suggesting the presence of cryptic bacteria in the collection culture of this fungus. In this study, intracellular bacteria were detected by fluorescence in situ hybridization in combination with confocal laser scanning microscopy in several collection subcultures of L. bicolor S238N. They were small (0.5 micro m in diameter), rare, and heterogeneously distributed in the mycelium and were identified as Paenibacillus spp. by using a 16S rRNA-directed oligonucleotide probe initially designed for bacteria isolated from a fermentor culture of L. bicolor S238N.
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Affiliation(s)
- J Bertaux
- Institut National de la Recherche Agronomique, UMR "Interactions Arbres/Micro-organismes," Centre de Nancy, 54280 Champenoux, France
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Roggy JC, Prévost MF, Gourbiere F, Casabianca H, Garbaye J, Domenach AM. Leaf natural 15N abundance and total N concentration as potential indicators of plant N nutrition in legumes and pioneer species in a rain forest of French Guiana. Oecologia 1999; 120:171-182. [PMID: 28308077 DOI: 10.1007/s004420050846] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The suitability of the natural 15N abundance and of total N concentration of leaves as indicators of the type of plant N nutrition in a rain forest of French Guiana were tested. Leaf samples from primary legume species, non-legumes (pioneer species) and from the non-N2-fixing species Dicorynia guianensis were analyzed. Both δ15N and total leaf N varied widely (-1 ?δ15N (‰) ? 7 and 1 ? leaf N(%) ? 3.2) suggesting possible distinctions between diazotrophic and non-fixing plants. The δ15N also revealed two statistically distinct groups of non-N2-fixing species (δ15N = 5.14 ± 0.3 vs δ15N = 1.65 ± 0.17) related to the different ecological behaviors of these species in the successional processes. We conclude that the δ15N signature of plant leaves combined with their total N concentration may be relevant indicators for identifying functional groups within the community of non-N2-fixing species, as well as for detecting diazotrophy. Despite the variability in the δ15N of the non-N2-fixing species, N2-fixing groups can still be identified, provided that plants are simultaneously classified taxonomically, by their leaf δ15N and total N concentration and by the presence or absence of nodules. The variability in the δ15N of the non-fixing species is discussed.
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Affiliation(s)
- J C Roggy
- Silvolab Guyane, Station de recherches forestières INRA BP 709, F-97387 Kourou Cedex, Guyane Française e-mail: , , , ,
| | - M F Prévost
- Silvolab Guyane, Laboratoire d'écologie végétale, ORSTOM, BP165, F-97323 Cayenne Cedex, Guyane Française, , , ,
| | - F Gourbiere
- Laboratoire d'écologie microbienne des sols, CNRS UMR, 5557 Université Claude Bernard Lyon1, 43 boulevard du 11 Novembre, F-69622 Villeurbanne Cedex, France, , , , , , FR
| | - H Casabianca
- Laboratoire Central d'Analyses CNRS, Echangeur de Solaize, BP 22, F-69390 Vernaison, France, , , , , , FR
| | - J Garbaye
- Laboratoire de Microbiologie forestière INRA, Centre de Nancy, F-54280 Champenoux, France, , , , , , FR
| | - A M Domenach
- Laboratoire d'écologie microbienne des sols, CNRS UMR, 5557 Université Claude Bernard Lyon1, 43 boulevard du 11 Novembre, F-69622 Villeurbanne Cedex, France, , , , , , FR
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Béreau M, Gazel M, Garbaye J. Les symbioses mycorhiziennes des arbres de la forêt tropicale humide de Guyane française. ACTA ACUST UNITED AC 1997. [DOI: 10.1139/b97-080] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Roots of 75 tree species, belonging to 28 families, were sampled on different types of soil in the forest of French Guiana. Both seedlings and mature trees of each species were studied. The roots were first observed for ectomycorrhizas, then thinned and stained to observe and quantify endomycorrhizal associations. Ectomycorrhizas were found only on two genera: Coccoloba (Polygonaceae) and Neea (Nyctaginaceae). All the species studied had zygomycetous endomycorrhizas with hyphal coils and vesicles. It is remarkable that some families (Caesalpiniaceae, Myrtaceae, Tiliaceae, Euphorbiaceae, Lauraceae), considered as frequently ectomycorrhizal in other regions of the world, were not so in our sample. In addition, the results contradict the theory that ectomycorrhizal species are dominant in the poorest soils in tropical rainforests (tropical podzols). Key words: tropical rainforest, symbioses, mycorrhizas, French Guiana.
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Béreau M, Louisanna E, Garbaye J. Effect of endomycorrhizas and nematodes on the growth of seedlings of Dicorynia guianensis Amshoff, a tree species of the tropical rain forest in French Guiana. ACTA ACUST UNITED AC 1997. [DOI: 10.1051/forest:19970305] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Devêvre O, Garbaye J, Botton B. Release of complexing organic acids by rhizosphere fungi as a factor in Norway spruce yellowing in acidic soils. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s0953-7562(96)80065-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
The symbiotic establishment of mycorrhizal fungi on plant roots is affected in various ways by the other microorganisms of the rhizosphere, and more especially by bacteria. This review discusses the case of some of these bacteria which consistently promote mycorrhizal development, leading to the concept of 'mycorrhization' helper bacteria (MHBs). Examples of MHB evidence are given from the literature, with special reference to the Douglas fir (Pseudotsuga menzeisii Mirb. Franco) Laccaria laccata Scop, ex Fr. ectomycorrhizal combination which has been more extensively studied. The fungal specificity of some MHBs and the various mechanisms underlying their effect are discussed, considering five hypotheses: effects on the receptivity of the root, effects on the root-fungus recognition, effects on the fungal growth, modification of the rhizospheric soil, and effects on the germination of the fungal propagule. MHBs are then considered for their ecological and evolutionary implications, and examples of practical applications in forest nurseries are given: when added to the fungal inoculum, MHBs can improve the success of ectomycorrhizal inoculation of planting stocks with fungi selected for their outstanding growth stimulation after outplanting. The conclusion points out a number of fundamental questions which remain unanswered about mycorrhization helper bacteria and suggests some investigation priorities in this new field of mycorrhiza research. Contents Summary 197 I. Introduction 197 II. Evidence for helper bacteria 198 III. Fungus-specificity of MHBs 200 IV. Mechanisms underlying the MHB effect 201 V. Ecological and evolutionary implications of MHBs 205 VI. Practical applications of MHBs 206 VII. Conclusions and perspectives 208 Acknowledgements 208 References 208.
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Affiliation(s)
- J Garbaye
- INRA, Centre de Recherches Forestieres de Nancy, 54280 Champenoux (France)
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Béreau M, Garbaye J. First observations on the root morphology and symbioses of 21 major tree species in the primary tropical rain forest of French Guyana. ACTA ACUST UNITED AC 1994. [DOI: 10.1051/forest:19940406] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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21
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Devêvre O, Roquebert MF, Garbaye J. Erste Resultate über den Effekt von Kalkung auf die Pilzpopulation (Saprophyten) im Ah-Horizont eines Fichtenwaldbodens in Frankreich (Vogesen). ACTA ACUST UNITED AC 1993. [DOI: 10.1007/bf02742138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ba AM, Garbaye J, Dexheimer J. Influence of fungal propagules during the early stage of the time sequence of ectomycorrhizal colonization on Afzelia africana seedlings. ACTA ACUST UNITED AC 1991. [DOI: 10.1139/b91-303] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A sequence of ectomycorrhizal colonization was observed on lateral roots of Afzelia africana Sm. seedlings. Four ectomycorrhizal types were obtained by a baiting method. Among the four types, two were recognized as occurring first in the ectomycorrhizal colonization sequence and the others occurred later. This sequence of ectomycorrhizal colonization was interpreted as follows: initial ectomycorrhizal types were related to the presence of vegetative propagules in the soil (mycorrhizal root fragments, fragments of mycelial strands, and sclerotia) and to the ability of the hyphae from these propagules to grow and quickly colonize Afzelia root systems. The time required for mycorrhizal colonization from spores, however, would be much longer. The types of mycorrhizal symbionts that were established first did not affect subsequent mycorrhizal colonization. An ultrastructural study suggested that vegetative propagules could function either as structures for long-term survival of the fungus in the soil or as structures for immediate opportunistic root colonization. Key words: ectomycorrhizal colonization, baiting method, fungal propagules, early stage fungi, Afzelia africana.
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Duponnois R, Garbaye J. Techniques for controlled synthesis of the Douglas-fir - Laccaria laccata ectomycorrhizal symbiosis. ACTA ACUST UNITED AC 1991. [DOI: 10.1051/forest:19910603] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Duponnois R, Garbaye J. Mycorrhization helper bacteria associated with the Douglas fir-Laccaria laccata symbiosis: effects in aseptic and in glasshouse conditions. ACTA ACUST UNITED AC 1991. [DOI: 10.1051/forest:19910301] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Abstract
The stimulating effect of some soil bacteria on the growth of two ectomycorrhizal fungi (Hebeloma crustuliniforme Bull. Saint Amans and Paxillus involutus Batsch. ex Fr.) is considered. Two mechanisms are involved: a direct trophic effect of the bacteria on the fungi, and an indirect effect by detoxication of the fungal culture medium. This is supported by observations that (i) some organic acids (citric acid, malic acid), released by the bacteria, stimulate the growth of the two fungi, and (ii) Paxillus involutus releases polyphenolic substances that are toxic to itself but are metabolized by the bacteria. These first results suggest that some bacteria can have beneficial effects during the saprophytic phase of ectomycorrhizal fungi before mycorrhizal infection.
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Guehl JM, Garbaye J. The effects of ectomycorrhizal status on carbon dioxide assimilation capacity, water-use efficiency and response to transplanting in seedlings of Pseudotsuga menziesii (Mirb) Franco. ACTA ACUST UNITED AC 1990. [DOI: 10.1051/forest:19900602] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Mauperin C, Mortier F, Garbaye J, Tacon FL, Carr G. Viability of an ectomycorrhizal inoculum produced in a liquid medium and entrapped in a calcium alginate gel. ACTA ACUST UNITED AC 1987. [DOI: 10.1139/b87-316] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Survival of Hebeloma crustuliniforme (Bulliard ex Fries) Quelet, grown in a liquid medium and subsequently entrapped in beads of calcium alginate, was tested under different conditions. Mycelium viability was not affected either by curing the beads for up to 22 h in 0.7 M CaCl2 or by the addition of either peat or bentonite to the alginate gel. Both peat and bentonite improved the water retention of the alginate gel, but only the incorporation of bentonite slowed down the rate at which moisture was lost by evaporation. At 4 °C the entrapped mycelium retained its viability for at least 5 months, provided that storage conditions remained humid. Partial drying of the beads reduced the effective storage time to a month. Emergence of hyphae from the beads was influenced by the presence of sterile soil extracts prepared from a podzolic soil, an acid brown earth, a mesotrophic brown earth, an eutrophic brown earth, and a rendzina. Hyphae grew out of all the beads containing peat irrespective of the type of soil extract but only grew out of those containing bentonite when they were on the mesotrophic brown earth extract. Hyphal emergence from beads containing neither peat nor bentonite appeared to be influenced by the pH of the extract, being better on those that were more acidic. Both sterile and nonsterile nursery soil supported growth of hyphae from the three types of bead, but on nonsterile soil, hyphae were not abundant and those that developed began to die off sooner than those on sterile soil.
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