RNA interference and nonviral targeted gene therapy of experimental brain cancer

According to isotopic labeling experiments, most of the carbon used by truffle (Tuber sp.) fruiting bodies to develop underground is provided by host trees, suggesting that trees and truffles are physically connected. However, such physical link between trees and truffle fruiting bodies has never been observed.We discovered fruiting bodies of Tuber aestivum adhering to the walls of a belowground quarry and we took advantage of this unique situation to analyze the physical structure that supported these fruiting bodies in the open air. Observation of transversal sections of the attachment structure indicated that it was organized in ducts made of gleba-like tissue and connected to a network of hyphae traveling across soil particles.Only one mating type was detected by PCR in the gleba and in the attachment structure, suggesting that these two organs are from maternal origin, leaving open the question of the location of the opposite paternal mating type

Forty years of inoculating seedlings with truffle fungi: past and future perspectives

The first commercialization of seedlings inoculated with truffle fungi occurred in 1973. Over the last 40 years, considerable progress has been made relative to quality control for inoculated seedlings. A recently published paper by Andr,s-Alpuente and colleagues (Mycorrhiza 24:29-37, 2014) reviewed and tested the different methods of mycorrhization assessment currently used in Europe. The aim of this paper is to augment their findings by adding information to the discussion about the most important steps in seedling quality control. Additionally, the history of seedlings inoculated with truffles, procedures currently used in France for seedling control quality, and a reflection on future research aimed at increasing truffle production will be presented

Studio della diversita genetica del tartufo bianco del Piemonte (Tuber magnatum Pico) e del tartufo nero del Perigord (Tuber melanosporum Vittad.)

Truffles are ectomycorrhizal fungi belonging to Tuber. Fructifications of some species, such as T. melanosporum and T. magnatum, are appreciated by consumers and have important economic value. Despite of numerous studies, some aspects of truffle biology (i.e. phylogeography and ecology) are unknown. Wide range analysis of genetic diversity in T. melanosporum showed important genetic differentiation between East and West French populations. Phylogeographic analysis allowed us to hypothesis that T. melanosporum recolonized France by two main routes : Rhône Valley route and Atlantic route. T. magnatum ascocarps analysis in a natural truffle ground identified at least two genotypes in this population. In order to characterize T. magnatum mycorrhizosphere, root tips have been harvested. We found that T. magnatum ectomycorrhizas are very rare (two out of 39 morphotypes). Moreover, more abundant species belong to Telephoraceae, Pezizales and Sebacina.Les truffes sont des champignons ectomycorhiziens du genre Tuber. De part leurs qualités organoleptiques, certaines espèces de truffes ont une forte valeur économique, c'est le cas de Tuber melanosporum et T. magnatum. Malgré la multiplication des études, il persiste de nombreuses inconnues sur la biologie (par exemple: phylogéographie et l'écologie) de ces espèces. L'analyse de la diversité génétique de T. melanosporum sur l'ensemble de son aire de répartition en France met en évidence un niveau de différenciation génétique non négligeable entre les populations de l'Est et de l'Ouest de la France. Une analyse phylogéographique a permis de suggérer deux voies de recolonisation post-glaciaire : la voie de la vallée du Rhône et la voie de l'Atlantique. L'analyse des ascocarpes de T. magnatum récoltés dans une truffière naturelle a montre l'existence d'au moins deux génotypes dans cette population. D'autre part, la récolte d'apex mycorhiziens indiquent que les ectomycorhizes de T. magnatum sont très rares (deux morphotypes sur 39). Les espèces ectomycorhiziennes majoritaires appartiennent aux Telephoraceae, Pezizales et Sebacina

Le génome de la truffe noire du Périgord

absen

Etude de la diversité génétique de la truffe blanche du Piémont (Tuber magnatum Pico) et de la truffe noire du Périgord (Tuber melanosporum Vittad.)

Les truffes sont des champignons ectomycorhiziens du genre Tuber. De part leurs qualités organoleptiques, certaines espèces de truffes ont une forte valeur économique, c'est le cas de Tuber melanosporum et T. magnatum. Malgré la multiplication des études, il persiste de nombreuses inconnues sur la biologie (par exemple: phylogéographie et l'écologie) de ces espèces. L'analyse de la diversité génétique de T. melanosporum sur l'ensemble de son aire de répartition en France met en évidence un niveau de différenciation génétique non négligeable entre les populations de l'Est et de l'Ouest de la France. Une analyse phylogéographique a permis de suggérer deux voies de recolonisation post-glaciaire : la voie de la vallée du Rhône et la voie de l'Atlantique. L'analyse des ascocarpes de T. magnatum récoltés dans une truffière naturelle a montre l'existence d'au moins deux génotypes dans cette population. D'autre part, la récolte d'apex mycorhiziens indiquent que les ectomycorhizes de T. magnatum sont très rares (deux morphotypes sur 39). Les espèces ectomycorhiziennes majoritaires appartiennent aux Telephoraceae, Pezizales et Sebacina.Truffles are ectomycorrhizal fungi belonging to Tuber. Fructifications of some species, such as T. melanosporum and T. magnatum, are appreciated by consumers and have important economic value. Despite of numerous studies, some aspects of truffle biology (i.e. phylogeography and ecology) are unknown. Wide range analysis of genetic diversity in T. melanosporum showed important genetic differentiation between East and West French populations. Phylogeographic analysis allowed us to hypothesis that T. melanosporum recolonized France by two main routes : Rhône Valley route and Atlantic route. T. magnatum ascocarps analysis in a natural truffle ground identified at least two genotypes in this population. In order to characterize T. magnatum mycorrhizosphere, root tips have been harvested. We found that T. magnatum ectomycorrhizas are very rare (two out of 39 morphotypes). Moreover, more abundant species belong to Telephoraceae, Pezizales and Sebacina.NANCY1-SCD Sciences & Techniques (545782101) / SudocSudocFranceF

Reconstructing the evolutionary history of gypsy retrotransposons in the Périgord black truffle (Tuber melanosporum Vittad.)

Truffles are ascomycete fungi belonging to genus Tuber, and they form ectomycorrhizal associations with trees and shrubs. Transposable elements constitute more than 50 % of the black Périgord truffle (Tuber melanosporum) genome, which are mainly class 1 gypsy retrotransposons, but their impact on its genome is unknown. The aims of this study are to investigate the diversity of gypsy retrotransposons in this species and their evolutionary history by analysing the reference genome and six resequenced genomes of different geographic accessions. Using the reverse transcriptase sequences, six different gypsy retrotransposon clades were identified. Tmt1 and Tmt6 are the most abundant transposable elements, representing 14 and 13 % of the T. melanosporum genome, respectively. Tmt6 showed a major burst of proliferation between 1 and 4 million years ago, but evidence of more recent transposition was observed. Except for Tmt2, the other clades tend to aggregate, and their mode of transposition excluded the master copy model. This suggests that each new copy has the same probability of transposing as other copies. This study provides a better view of the diversity and dynamic nature of gypsy retrotransposons in T. melanosporum. Even if the major gypsy retrotransposon bursts are old, some elements seem to have transposed recently, suggesting that they may continue to model the truffle genomes

Au cœur de la truffe noire

absen

Identification and In Situ Distribution of a Fungal Gene Marker: The Mating Type Genes of the Black Truffle

Truffles are ectomycorrhizal fungi harvested mainly in human managed agroforestry ecosystems. Truffle production in truffle orchards faces two important bottlenecks or challenges: the initiation of the sexual reproduction and the growth of the ascocarps during several months. The black Périgord truffle, Tuber melanosporum, is a heterothallic species and the mating type genes (MAT1-1 and M1T1-2) have been characterized. In this context, the unraveling of the T. melanosporum mating type strains distribution in truffle orchards is a critical starting point to provide new insights into its sexual reproduction. The aim of this chapter is to present the protocol used to characterize the T. melanosporum mating type present in a truffle orchard from ascocarps, hazel mycorrhizal root tips, and/or soil samples, by polymerase chain reactions using specific primers for those genes, but it can be adapted for other fungal species

Fungal diversity is not determined by mineral and chemical differences in serpentine substrates

The physico-chemical properties of serpentine soils lead to strong selection of plant species. Whereas many studies have described the serpentine flora, little information is available on the fungal communities dwelling in these sites. Asbestos minerals, often associated with serpentine rocks, can be weathered by serpentine-isolated fungi, suggesting an adaptation to this substrate. In this study, we have investigated whether serpentine substrates characterized by the presence of rocks with distinct mineral composition could select for different fungal communities. Both fungal isolation and 454 pyrosequencing of amplicons obtained from serpentine samples following direct DNA extraction revealed some fungal taxa shared by the four ophiolitic substrates, but also highlighted several substrate-specific taxa. Bootstrap analysis of 454 OTU abundances indicated weak clustering of fungal assemblages from the different substrates, which did not match substrate classification based on exchangeable macronutrients and metals. Intra-substrate variability, as assessed by DGGE profiles, was similar across the four serpentine substrates, and comparable to inter-substrate variability. These findings indicate the absence of a correlation between the substrate ( mineral composition and available cations) and the diversity of the fungal community. Comparison of culture-based and culture-independent methods supports the higher taxonomic precision of the former, as complementation of the better performance of the latter