The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
François Le Tacon - One of the best experts on this subject based on the ideXlab platform.
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Carbon Transfer from the Host to Tuber melanosporum Mycorrhizas and Ascocarps Followed Using a 13C Pulse- Labeling Technique
2016Co-Authors: François Le Tacon, Caroline Plain, Bernd Zeller, Christian HossannAbstract:Truffles Ascocarps need carbon to grow, but it is not known whether this carbon comes directly from the tree (heterotrophy) or from soil organic matter (saprotrophy). The objective of this work was to investigate the heterotrophic side of the Ascocarp nutrition by assessing the allocation of carbon by the host to Tuber melanosporum mycorrhizas and Ascocarps. In 2010, a single hazel tree selected for its high truffle (Tuber melanosporum) production and situated in the west part of the Vosges, France, was labeled with 13CO2. The transfer of 13C from the leaves to the fine roots and T. melanosporum mycorrhizas was very slow compared with the results found in the literature for herbaceous plants or other tree species. The fine roots primarily acted as a carbon conduit; they accumulated little 13C and transferred it slowly to the mycorrhizas. The mycorrhizas first formed a carbon sink and accumulated 13C prior to Ascocarp development. Then, the mycorrhizas transferred 13C to the Ascocarps to provide constitutive carbon (1.7 mg of 13C per day). The Ascocarps accumulated host carbon until reaching complete maturity, 200 days after the first labeling and 150 days after the second labeling event. This role of the Tuber Ascocarps as a carbon sink occurred several months after the end of carbon assimilation by the host and a
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Certainties and uncertainties about the life cycle of the Périgord black truffle (Tuber melanosporum Vittad.)
Annals of Forest Science, 2016Co-Authors: François Le Tacon, Christophe Robin, Bernd Zeller, Andrea Rubini, Claude Murat, Claudia Riccioni, Beatrice Belfiori, Herminia Varga, Emila Akroume, Aurelie DeveauAbstract:• Key message Several aspects of the life cycle of the Périgord black truffle have been elucidated only recently, while others remain either controversial or unstudied. In this paper, we present a revised life cycle of this fungus and highlight key aspects that have yet to be addressed or require further understanding. • Context The hypogeous sporophores of several Tuber species, renowned for their aromatic and gustatory qualities, are widely commercialized. One of the most valuable species is Tuber melanosporum Vittad., the Périgord black truffle also known as “the black diamond”. However, many aspects of T. melanosporum life cycle remain unsolved. • Aims In this work, we examine past and recent findings on the life cycle of T. melanosporum , currently regarded as a model system for Tuber species, with the view of highlighting aspects of its life cycle which remain unsolved. • Results Several aspects of its life cycle have recently been elucidated (i.e. characterization of two mating type genes, heterothallism, prevalence of sexual reproduction on vegetative propagation, exclusion of one mating type by its opposite on ectomycorrhizas, dependency of Ascocarps on their host for carbon allocation), while others remain unaddressed. • Conclusion Numerous additional aspects of the T. melanosporum life cycle remain unsolved, such as exclusion or competition mechanisms between ectomycorrhizal mating types, factors involved in Ascocarp initiation, the nature of the connection linking Ascocarps and mycorrhizas and atmospheric nitrogen fixation.
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Symbiotic versus saprotrophic strategy during Tuber melanosporum Ascocarp development. Preliminary results based on 13C and 15N natural abundance and on in situ 13CO2 pulse-labelling
2015Co-Authors: François Le Tacon, Bernhard Zeller, Caroline Plain, Christian Hossann, Christophe Robin, Jean-paul Maurice, Claude BrechetAbstract:Despite their renown, the life cycle of the true truffles belonging to the genus Tuberis not well known. The growth of the Ascocarp is poorly understood. It is not known if a direct transfer of carbohydrates takes place between the host tree and the developing Ascocarps through the ascogonial filament or whether Ascocarps become independent from their hosts after several weeks or months and are able to use dead host tissues or soil organic matter as carbon and nitrogen sources. From a first work based on 13C and 15N natural abundance, we found that Tuber Ascocarps do not exhibit a saprotrophic strategy during their development [1]. However, in situ13C and 15N labelling experiments are the only way to solve the question of carbon and nitrogen allocation during Tuber Ascocarp differentiation. A first in situ13CO2pulse-labelling experiment was carried out in 2010 on a 20-year-old hazel tree mycorrhized with Tuber melanosporum. The preliminary results showed that the transfer of carbon from the leaves to the fine roots is slow but continuous during several months even during winter at low temperature. The fine roots act as a pipe to transfer the carbon to the mycorrhizas. From the mycorrhizas,13C accumulates into the Ascocarps, which constitutes a carbon sink. These results contradict the statements of recognized truffle handbooks and could be of some importance for the improvement of truffle cultivation methods.
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Carbon Transfer from the Host to Tuber melanosporum Mycorrhizas and Ascocarps Followed Using a 13C Pulse-Labeling Technique
PLOS ONE, 2013Co-Authors: François Le Tacon, Bernhard Zeller, Caroline Plain, Christian Hossann, Claude Brechet, Christophe RobinAbstract:Truffles Ascocarps need carbon to grow, but it is not known whether this carbon comes directly from the tree (heterotrophy) or from soil organic matter (saprotrophy). The objective of this work was to investigate the heterotrophic side of the Ascocarp nutrition by assessing the allocation of carbon by the host to Tuber melanosporum mycorrhizas and Ascocarps. In 2010, a single hazel tree selected for its high truffle (Tuber melanosporum) production and situated in the west part of the Vosges, France, was labeled with 13CO2. The transfer of 13C from the leaves to the fine roots and T. melanosporum mycorrhizas was very slow compared with the results found in the literature for herbaceous plants or other tree species. The fine roots primarily acted as a carbon conduit; they accumulated little 13C and transferred it slowly to the mycorrhizas. The mycorrhizas first formed a carbon sink and accumulated 13C prior to Ascocarp development. Then, the mycorrhizas transferred 13C to the Ascocarps to provide constitutive carbon (1.7 mg of 13C per day). The Ascocarps accumulated host carbon until reaching complete maturity, 200 days after the first labeling and 150 days after the second labeling event. This role of the Tuber Ascocarps as a carbon sink occurred several months after the end of carbon assimilation by the host and at low temperature. This finding suggests that carbon allocated to the Ascocarps during winter was provided by reserve compounds stored in the wood and hydrolyzed during a period of frost. Almost all of the constitutive carbon allocated to the truffles (1% of the total carbon assimilated by the tree during the growing season) came from the host.
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Saprotrophic versus symbiotic strategy during truffle Ascocarp development under holm oak. A response based on 13C and 15N natural abundance
Annals of Forest Science, 2008Co-Authors: Bernd Zeller, Claude Brechet, Jean-paul Maurice, François Le TaconAbstract:• The development of truffles in the soil is not well understood. It is not known if a direct transfer of carbohydrates takes place between the host tree and the developing Ascocarps through ectomycorrhizal structures or whether sporophores become independent from their hosts after several weeks or months and are able to use dead host tissues or soil organic matter as carbon (C) and nitrogen (N) sources. • To study saprophytic or symbiotic capacities of truffle Ascocarps the natural abundance of 15 Na nd 13 C in foliage, wood, fine roots, mycorrhizae, fungal sporophores and soil were determined in a truffle orchard. • The processes of carbon and nitrogen allocation remained unchanged during the entire period of Ascocarp development of Tuber melanosporum. From 13 Ca nd 15 N natural abundance measurements, T. melanosporum, T. brumale and T. rufum did not exhibit saprotophic strategy during Ascocarp development, which is contradictory to common statements found in handbooks regarding truffle cultivation. 13 C / 15 N / Tuber melanosporum / Tuber brumale / Tuber rufum / Ascocarps development
Christophe Robin - One of the best experts on this subject based on the ideXlab platform.
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Certainties and uncertainties about the life cycle of the Périgord black truffle (Tuber melanosporum Vittad.)
Annals of Forest Science, 2016Co-Authors: François Le Tacon, Christophe Robin, Bernd Zeller, Andrea Rubini, Claude Murat, Claudia Riccioni, Beatrice Belfiori, Herminia Varga, Emila Akroume, Aurelie DeveauAbstract:• Key message Several aspects of the life cycle of the Périgord black truffle have been elucidated only recently, while others remain either controversial or unstudied. In this paper, we present a revised life cycle of this fungus and highlight key aspects that have yet to be addressed or require further understanding. • Context The hypogeous sporophores of several Tuber species, renowned for their aromatic and gustatory qualities, are widely commercialized. One of the most valuable species is Tuber melanosporum Vittad., the Périgord black truffle also known as “the black diamond”. However, many aspects of T. melanosporum life cycle remain unsolved. • Aims In this work, we examine past and recent findings on the life cycle of T. melanosporum , currently regarded as a model system for Tuber species, with the view of highlighting aspects of its life cycle which remain unsolved. • Results Several aspects of its life cycle have recently been elucidated (i.e. characterization of two mating type genes, heterothallism, prevalence of sexual reproduction on vegetative propagation, exclusion of one mating type by its opposite on ectomycorrhizas, dependency of Ascocarps on their host for carbon allocation), while others remain unaddressed. • Conclusion Numerous additional aspects of the T. melanosporum life cycle remain unsolved, such as exclusion or competition mechanisms between ectomycorrhizal mating types, factors involved in Ascocarp initiation, the nature of the connection linking Ascocarps and mycorrhizas and atmospheric nitrogen fixation.
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Symbiotic versus saprotrophic strategy during Tuber melanosporum Ascocarp development. Preliminary results based on 13C and 15N natural abundance and on in situ 13CO2 pulse-labelling
2015Co-Authors: François Le Tacon, Bernhard Zeller, Caroline Plain, Christian Hossann, Christophe Robin, Jean-paul Maurice, Claude BrechetAbstract:Despite their renown, the life cycle of the true truffles belonging to the genus Tuberis not well known. The growth of the Ascocarp is poorly understood. It is not known if a direct transfer of carbohydrates takes place between the host tree and the developing Ascocarps through the ascogonial filament or whether Ascocarps become independent from their hosts after several weeks or months and are able to use dead host tissues or soil organic matter as carbon and nitrogen sources. From a first work based on 13C and 15N natural abundance, we found that Tuber Ascocarps do not exhibit a saprotrophic strategy during their development [1]. However, in situ13C and 15N labelling experiments are the only way to solve the question of carbon and nitrogen allocation during Tuber Ascocarp differentiation. A first in situ13CO2pulse-labelling experiment was carried out in 2010 on a 20-year-old hazel tree mycorrhized with Tuber melanosporum. The preliminary results showed that the transfer of carbon from the leaves to the fine roots is slow but continuous during several months even during winter at low temperature. The fine roots act as a pipe to transfer the carbon to the mycorrhizas. From the mycorrhizas,13C accumulates into the Ascocarps, which constitutes a carbon sink. These results contradict the statements of recognized truffle handbooks and could be of some importance for the improvement of truffle cultivation methods.
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Black truffle-associated bacterial communities during the development and maturation of Tuber melanosporum Ascocarps and putative functional roles.
Environmental Microbiology, 2014Co-Authors: Sanjay Antony-babu, Christophe Robin, Pascale Frey-klett, Aurelie Deveau, Joy D Van Nostrand, Jizhong Zhou, Francois Le Tacon, Stéphane UrozAbstract:Although truffles are cultivated since decades, their life cycle and the conditions stimulating Ascocarp formation still remain mysterious. A role for bacteria in the development of several truffle species has been suggested but few is known regarding the natural bacterial communities of Périgord Black truffle. Thus, the aim of this study was to decipher the structure and the functional potential of the bacterial communities associated to the Black truffle in the course of its life cycle and along truffle maturation. A polyphasic approach combining 454-pyrosequencing of 16S rRNA gene, TTGE, in situ hybridization and functional GeoChip 3.0 revealed that Black truffle Ascocarps provide a habitat to complex bacterial communities that are clearly differentiated from those of the surrounding soil and the ectomycorrhizosphere. The composition of these communities is dynamic and evolves during the maturation of the Ascocarps with an enrichment of specific taxa and a differentiation of the gleba and peridium-associated bacterial communities. Genes related to nitrogen and sulphur cycling were enriched in the Ascocarps. Together, these data paint a new picture of the interactions existing between truffle and bacteria and of the potential role of these bacteria in truffle maturation.
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Black truffle‐associated bacterial communities during the development and maturation of Tuber melanosporum Ascocarps and putative functional roles
Environmental microbiology, 2013Co-Authors: Sanjay Antony-babu, Christophe Robin, Pascale Frey-klett, Aurelie Deveau, Joy D Van Nostrand, Jizhong Zhou, Francois Le Tacon, Stéphane UrozAbstract:Although truffles are cultivated since decades, their life cycle and the conditions stimulating Ascocarp formation still remain mysterious. A role for bacteria in the development of several truffle species has been suggested but few is known regarding the natural bacterial communities of Perigord Black truffle. Thus, the aim of this study was to decipher the structure and the functional potential of the bacterial communities associated to the Black truffle in the course of its life cycle and along truffle maturation. A polyphasic approach combining 454-pyrosequencing of 16S rRNA gene, TTGE, in situ hybridization and functional GeoChip 3.0 revealed that Black truffle Ascocarps provide a habitat to complex bacterial communities that are clearly differentiated from those of the surrounding soil and the ectomycorrhizosphere. The composition of these communities is dynamic and evolves during the maturation of the Ascocarps with an enrichment of specific taxa and a differentiation of the gleba and peridium-associated bacterial communities. Genes related to nitrogen and sulphur cycling were enriched in the Ascocarps. Together, these data paint a new picture of the interactions existing between truffle and bacteria and of the potential role of these bacteria in truffle maturation.
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Carbon Transfer from the Host to Tuber melanosporum Mycorrhizas and Ascocarps Followed Using a 13C Pulse-Labeling Technique
PLOS ONE, 2013Co-Authors: François Le Tacon, Bernhard Zeller, Caroline Plain, Christian Hossann, Claude Brechet, Christophe RobinAbstract:Truffles Ascocarps need carbon to grow, but it is not known whether this carbon comes directly from the tree (heterotrophy) or from soil organic matter (saprotrophy). The objective of this work was to investigate the heterotrophic side of the Ascocarp nutrition by assessing the allocation of carbon by the host to Tuber melanosporum mycorrhizas and Ascocarps. In 2010, a single hazel tree selected for its high truffle (Tuber melanosporum) production and situated in the west part of the Vosges, France, was labeled with 13CO2. The transfer of 13C from the leaves to the fine roots and T. melanosporum mycorrhizas was very slow compared with the results found in the literature for herbaceous plants or other tree species. The fine roots primarily acted as a carbon conduit; they accumulated little 13C and transferred it slowly to the mycorrhizas. The mycorrhizas first formed a carbon sink and accumulated 13C prior to Ascocarp development. Then, the mycorrhizas transferred 13C to the Ascocarps to provide constitutive carbon (1.7 mg of 13C per day). The Ascocarps accumulated host carbon until reaching complete maturity, 200 days after the first labeling and 150 days after the second labeling event. This role of the Tuber Ascocarps as a carbon sink occurred several months after the end of carbon assimilation by the host and at low temperature. This finding suggests that carbon allocated to the Ascocarps during winter was provided by reserve compounds stored in the wood and hydrolyzed during a period of frost. Almost all of the constitutive carbon allocated to the truffles (1% of the total carbon assimilated by the tree during the growing season) came from the host.
Claude Brechet - One of the best experts on this subject based on the ideXlab platform.
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Symbiotic versus saprotrophic strategy during Tuber melanosporum Ascocarp development. Preliminary results based on 13C and 15N natural abundance and on in situ 13CO2 pulse-labelling
2015Co-Authors: François Le Tacon, Bernhard Zeller, Caroline Plain, Christian Hossann, Christophe Robin, Jean-paul Maurice, Claude BrechetAbstract:Despite their renown, the life cycle of the true truffles belonging to the genus Tuberis not well known. The growth of the Ascocarp is poorly understood. It is not known if a direct transfer of carbohydrates takes place between the host tree and the developing Ascocarps through the ascogonial filament or whether Ascocarps become independent from their hosts after several weeks or months and are able to use dead host tissues or soil organic matter as carbon and nitrogen sources. From a first work based on 13C and 15N natural abundance, we found that Tuber Ascocarps do not exhibit a saprotrophic strategy during their development [1]. However, in situ13C and 15N labelling experiments are the only way to solve the question of carbon and nitrogen allocation during Tuber Ascocarp differentiation. A first in situ13CO2pulse-labelling experiment was carried out in 2010 on a 20-year-old hazel tree mycorrhized with Tuber melanosporum. The preliminary results showed that the transfer of carbon from the leaves to the fine roots is slow but continuous during several months even during winter at low temperature. The fine roots act as a pipe to transfer the carbon to the mycorrhizas. From the mycorrhizas,13C accumulates into the Ascocarps, which constitutes a carbon sink. These results contradict the statements of recognized truffle handbooks and could be of some importance for the improvement of truffle cultivation methods.
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Carbon Transfer from the Host to Tuber melanosporum Mycorrhizas and Ascocarps Followed Using a 13C Pulse-Labeling Technique
PLOS ONE, 2013Co-Authors: François Le Tacon, Bernhard Zeller, Caroline Plain, Christian Hossann, Claude Brechet, Christophe RobinAbstract:Truffles Ascocarps need carbon to grow, but it is not known whether this carbon comes directly from the tree (heterotrophy) or from soil organic matter (saprotrophy). The objective of this work was to investigate the heterotrophic side of the Ascocarp nutrition by assessing the allocation of carbon by the host to Tuber melanosporum mycorrhizas and Ascocarps. In 2010, a single hazel tree selected for its high truffle (Tuber melanosporum) production and situated in the west part of the Vosges, France, was labeled with 13CO2. The transfer of 13C from the leaves to the fine roots and T. melanosporum mycorrhizas was very slow compared with the results found in the literature for herbaceous plants or other tree species. The fine roots primarily acted as a carbon conduit; they accumulated little 13C and transferred it slowly to the mycorrhizas. The mycorrhizas first formed a carbon sink and accumulated 13C prior to Ascocarp development. Then, the mycorrhizas transferred 13C to the Ascocarps to provide constitutive carbon (1.7 mg of 13C per day). The Ascocarps accumulated host carbon until reaching complete maturity, 200 days after the first labeling and 150 days after the second labeling event. This role of the Tuber Ascocarps as a carbon sink occurred several months after the end of carbon assimilation by the host and at low temperature. This finding suggests that carbon allocated to the Ascocarps during winter was provided by reserve compounds stored in the wood and hydrolyzed during a period of frost. Almost all of the constitutive carbon allocated to the truffles (1% of the total carbon assimilated by the tree during the growing season) came from the host.
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Saprotrophic versus symbiotic strategy during truffle Ascocarp development under holm oak. A response based on 13C and 15N natural abundance
Annals of Forest Science, 2008Co-Authors: Bernd Zeller, Claude Brechet, Jean-paul Maurice, François Le TaconAbstract:• The development of truffles in the soil is not well understood. It is not known if a direct transfer of carbohydrates takes place between the host tree and the developing Ascocarps through ectomycorrhizal structures or whether sporophores become independent from their hosts after several weeks or months and are able to use dead host tissues or soil organic matter as carbon (C) and nitrogen (N) sources. • To study saprophytic or symbiotic capacities of truffle Ascocarps the natural abundance of 15 Na nd 13 C in foliage, wood, fine roots, mycorrhizae, fungal sporophores and soil were determined in a truffle orchard. • The processes of carbon and nitrogen allocation remained unchanged during the entire period of Ascocarp development of Tuber melanosporum. From 13 Ca nd 15 N natural abundance measurements, T. melanosporum, T. brumale and T. rufum did not exhibit saprotophic strategy during Ascocarp development, which is contradictory to common statements found in handbooks regarding truffle cultivation. 13 C / 15 N / Tuber melanosporum / Tuber brumale / Tuber rufum / Ascocarps development
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Saprotrophic versus symbiotic strategy during truffle Ascocarp development under holm oak. A response based on 13C and 15N natural abundance
Annals of Forest Science, 2008Co-Authors: Bernhard Zeller, Claude Brechet, Jean-paul Maurice, François Le TaconAbstract:The development of truffles in the soil is not well understood. It is not known if a direct transfer of carbohydrates takes place between the host tree and the developing Ascocarps through ectomycorrhizal structures or whether sporophores become independent from their hosts after several weeks or months and are able to use dead host tissues or soil organic matter as carbon (C) and nitrogen (N) sources. To study saprophytic or symbiotic capacities of truffle Ascocarps the natural abundance of 15N and 13C in foliage, wood, fine roots, mycorrhizae, fungal sporophores and soil were determined in a truffle orchard. The processes of carbon and nitrogen allocation remained unchanged during the entire period of Ascocarp development of Tuber melanosporum. From 13C and 15N natural abundance measurements, T. melanosporum, T. brumale and T. rufum did not exhibit saprotophic strategy during Ascocarp development, which is contradictory to common statements found in handbooks regarding truffle cultivation.
W. F. Pfender - One of the best experts on this subject based on the ideXlab platform.
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Effect of wetting-period duration on Ascocarp suppression by selected antagonistic fungi in wheat straw infested with Pyrenophora tritici-repentis
Phytopathology, 1993Co-Authors: Wei Zhang, W. F. PfenderAbstract:Wheat straw axenically or naturally infested with Pyrenophora tritici-repentis was inoculated with one of several antagonistic fungi and exposed to various treatments of alternate wetting and drying, and Ascocarp production by P. tritici-repentis on straw was measured. Wetting treatments were repeated wet periods of 6, 12, 24, or 48 h separated by drying periods. In the absence of suppressive fungi, Ascocarp formation by P. tritici-repentis was observed in both axenically colonized straw and naturally infested field straw in all wetting treatments, and the effect of wetting duration on Ascocarp formation was not obvious. Suppression of Ascocarp formation in both field and axenic straw by selected antagonistic fungi was affected by the duration of intermittent wetting [...]
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Effect of residue management on wetness duration and Ascocarp production by Pyrenophora tritici-repentis in wheat residue.
Phytopathology, 1992Co-Authors: W. Zhang, W. F. PfenderAbstract:No-till, mowed, and disked residue treatments were applied to wheat residue infested with Pyrenophora tritici-repentis in fields near Manhattan, KS, in 1988 and 1989. Ascocarp production by P. tritici-repentis and straw-wetness duration were studied in relation to these treatments and four straw positions relative to the soil surface (above-soil and near-soil; upper part and lower part of standing stubble). Ascocarp production, estimated by counting Ascocarps on sampled straw, was significantly affected by straw position and tillage treatment []
Bernhard Zeller - One of the best experts on this subject based on the ideXlab platform.
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Symbiotic versus saprotrophic strategy during Tuber melanosporum Ascocarp development. Preliminary results based on 13C and 15N natural abundance and on in situ 13CO2 pulse-labelling
2015Co-Authors: François Le Tacon, Bernhard Zeller, Caroline Plain, Christian Hossann, Christophe Robin, Jean-paul Maurice, Claude BrechetAbstract:Despite their renown, the life cycle of the true truffles belonging to the genus Tuberis not well known. The growth of the Ascocarp is poorly understood. It is not known if a direct transfer of carbohydrates takes place between the host tree and the developing Ascocarps through the ascogonial filament or whether Ascocarps become independent from their hosts after several weeks or months and are able to use dead host tissues or soil organic matter as carbon and nitrogen sources. From a first work based on 13C and 15N natural abundance, we found that Tuber Ascocarps do not exhibit a saprotrophic strategy during their development [1]. However, in situ13C and 15N labelling experiments are the only way to solve the question of carbon and nitrogen allocation during Tuber Ascocarp differentiation. A first in situ13CO2pulse-labelling experiment was carried out in 2010 on a 20-year-old hazel tree mycorrhized with Tuber melanosporum. The preliminary results showed that the transfer of carbon from the leaves to the fine roots is slow but continuous during several months even during winter at low temperature. The fine roots act as a pipe to transfer the carbon to the mycorrhizas. From the mycorrhizas,13C accumulates into the Ascocarps, which constitutes a carbon sink. These results contradict the statements of recognized truffle handbooks and could be of some importance for the improvement of truffle cultivation methods.
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Carbon Transfer from the Host to Tuber melanosporum Mycorrhizas and Ascocarps Followed Using a 13C Pulse-Labeling Technique
PLOS ONE, 2013Co-Authors: François Le Tacon, Bernhard Zeller, Caroline Plain, Christian Hossann, Claude Brechet, Christophe RobinAbstract:Truffles Ascocarps need carbon to grow, but it is not known whether this carbon comes directly from the tree (heterotrophy) or from soil organic matter (saprotrophy). The objective of this work was to investigate the heterotrophic side of the Ascocarp nutrition by assessing the allocation of carbon by the host to Tuber melanosporum mycorrhizas and Ascocarps. In 2010, a single hazel tree selected for its high truffle (Tuber melanosporum) production and situated in the west part of the Vosges, France, was labeled with 13CO2. The transfer of 13C from the leaves to the fine roots and T. melanosporum mycorrhizas was very slow compared with the results found in the literature for herbaceous plants or other tree species. The fine roots primarily acted as a carbon conduit; they accumulated little 13C and transferred it slowly to the mycorrhizas. The mycorrhizas first formed a carbon sink and accumulated 13C prior to Ascocarp development. Then, the mycorrhizas transferred 13C to the Ascocarps to provide constitutive carbon (1.7 mg of 13C per day). The Ascocarps accumulated host carbon until reaching complete maturity, 200 days after the first labeling and 150 days after the second labeling event. This role of the Tuber Ascocarps as a carbon sink occurred several months after the end of carbon assimilation by the host and at low temperature. This finding suggests that carbon allocated to the Ascocarps during winter was provided by reserve compounds stored in the wood and hydrolyzed during a period of frost. Almost all of the constitutive carbon allocated to the truffles (1% of the total carbon assimilated by the tree during the growing season) came from the host.
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Saprotrophic versus symbiotic strategy during truffle Ascocarp development under holm oak. A response based on 13C and 15N natural abundance
Annals of Forest Science, 2008Co-Authors: Bernhard Zeller, Claude Brechet, Jean-paul Maurice, François Le TaconAbstract:The development of truffles in the soil is not well understood. It is not known if a direct transfer of carbohydrates takes place between the host tree and the developing Ascocarps through ectomycorrhizal structures or whether sporophores become independent from their hosts after several weeks or months and are able to use dead host tissues or soil organic matter as carbon (C) and nitrogen (N) sources. To study saprophytic or symbiotic capacities of truffle Ascocarps the natural abundance of 15N and 13C in foliage, wood, fine roots, mycorrhizae, fungal sporophores and soil were determined in a truffle orchard. The processes of carbon and nitrogen allocation remained unchanged during the entire period of Ascocarp development of Tuber melanosporum. From 13C and 15N natural abundance measurements, T. melanosporum, T. brumale and T. rufum did not exhibit saprotophic strategy during Ascocarp development, which is contradictory to common statements found in handbooks regarding truffle cultivation.
