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Jaillard B.,French National Institute for Agricultural Research | Barry-Etienne D.,Alcina | Colinas C.,Center Tecnologic Forestal Of Catalonia | Colinas C.,University of Lleida | And 11 more authors.
Forest Systems | Year: 2014

Aim of study: The program "Typology of truffle stations in the Pyrenean Regions" aimed to define the ecological conditions and culture practices that favor Tuber melanosporum growth and fruiting in this area. Area of study: Navarra, Catalonia, Midi-Pyrénées and Languedoc-Roussillon. Material and methods: The program was based on the survey of 212 wild and cultivated truffle beds of evergreen oaks (Quercus ilex). The data collected in the field consisted of photographs, samples of soil, roots and mycorrhizae, and information on cultural practices followed by truffle growers. Main results: (i) truffle soils are alkaline, from neutral, dolomitic, to moderately or very calcareous soils; (ii) truffle soils are light, well-structured and stable to water immersion; (iii) mycelium that colonizes roots survives in suboptimal conditions, but it does not necessarily bear ascocarps. Finally our results suggest that T. melanosporum is a relatively ubiquitous fungus able to grow, or at least to persist, in a wide range of physical and chemical soil conditions. We propose a probabilistic model of the environment favorable for fruiting, built around a two-dimensional graph with an axis for the chemical conditions, like soil alkalinity, and another axis for the physical conditions, like soil structure. Research highlights: Soil alkalinity and structure allow to built a convenient representation of the ecological capacity of a place to be good T. melanosporum habitat, and thus of the probability for truffle growers to harvest truffles according to the environmental properties of their truffle orchards.

Napoli C.,University of Turin | Mello A.,CNR Plant Protection Institute | Borra A.,University of Turin | Vizzini A.,University of Turin | And 3 more authors.
New Phytologist | Year: 2010

The fruiting bodies of the ectomycorrhizal (ECM) fungus Tuber melanosporum are usually collected in an area devoid of vegetation which is defined as a 'burnt area' (brulé in French). Here, the soil fungal populations of inside and outside brulé were compared in order to understand whether the scanty plant cover was related to a change in fungal biodiversity. Both denaturing gradient gel electrophoresis (DGGE) and molecular cloning of the internal transcribed spacer (ITS) marker were employed on soil DNA to obtain profiles from nine truffle grounds and fungal sequences from one selected truffle ground sampled in two years. Denaturant gradient gel electrophoresis profiles from the two areas formed two distinct clusters while molecular cloning allowed 417 fungal sequences to be identified. T. melanosporum was the dominant fungus within the brulé. There were nine new haplotypes, which had never been detected in fruiting bodies. The Basidiomycota ECM fungi decreased within the brulé, indicating a competitive effect of T. melanosporum on the other ECM fungi. Among other factors, the dynamics of fungal populations seems to be correlated to brulé formation. © 2009 New Phytologist.

Loading Station dExperimentation sur la Truffe collaborators
Loading Station dExperimentation sur la Truffe collaborators