Kurzbeschreibung
(Englisch)
|
Several truffle species (Tuber spp.) are highly appreciated as delicacies on the international market. Their ecological drivers and geographical patterns, particularly in Central Europe north of the traditional Mediterranean habitats, though often remain puzzling. Our herein proposed research project will study the complex biotic and abiotic ecology of the Burgundy truffle (Tuber aestivum) in Switzerland and the German pre-Alps. We will place particular emphasis on a combination of population genetic information with climatological and physiological factors and processes relevant for the productivity and phenology of this most valuable truffle species, which recently receives growing cultivation interest across Europe. We will evaluate small scale spatial patterns and - dynamics of T. aestivum individuals and mating types in natural truffle habitats and in newly established truffle plantations. A second part of this project will deal with the analysis of large-scale population structures in truffle monitoring sites and the link between these genetic to environmental and habitat data. Results of this project will support basic knowledge of the life history of this truffle species for a sustainable use and cultivation of a valuable non-wood forest product.
|
Abstract
(Englisch)
|
Truffles are ascomycetes belonging to the Tuber genus of which many are precious edible fungi. Tuber aestivum (Vitt.), known as the Burgundy truffle and esteemed as a valuable non-wood forest product, is found all over Europe, from Sweden to Spain. Whether it consists of different genetic ecotypes and how it completes its life cycle is largely unknown. Our project focuses on the complex biotic and abiotic ecology of this species. We place particular emphasis on a combination of population genetic information with climatological and physiological factors and processes relevant for the productivity and phenology of this truffle species. In a first part of the project, we evaluate smallscale spatial patterns and -dynamics of T. aestivum individuals and mating types in natural truffle habitats and in newly established truffle plantations to better understand the life cycle of this species. A second part deals with the analysis of large-scale population structures in truffle monitoring sites and the link between these genetic to environmental and habitat data. This allows studying the phenology and ecological drivers of fruit body production. For the first part, a fine scale genetic structure study was performed in two monitoring sites. It revealed the existence of 4 genetic groups, two groups in each site, which seem not to be spatially separated indicating that biological or ecological barriers may exist for gene flow. Both sites show many individuals on small spatial scales but with some clones reaching sizes of over 100m. In newly established truffle plantations, a first sampling of genotype compositions at the roots and the mycelial growth in the soils were performed. Since the plants are still small and fragile, we decided not to continue the monitoring in these plantations every year as planned but only every second one. Instead, to fill the gap between artificial and natural truffle sites, we collected fruit bodies, roots and soil within a highly productive truffle site in Hungary in August 2014. It well complements the small-scale spatial studies in that it represents a regular plantation of Quercus spp that were naturally colonized by T. aestivum. It allows studying the genetic structure of this truffle species in a homogenous environment, as is the case in artificial truffle orchards but unlike these, representing a natural population. For the second part of the project, 16 natural truffle grounds in Switzerland and Southwest Germany are continuously monitored since 2011 or 2013 for fruit body production, soil temperature, humidity and tree growth. Truffle fruit bodies are collected every three weeks all over the year to assess the temporal genetic patterns of truffle populations. Vegetation and soil parameter surveys were carried out in 2014 for each monitoring site. Soil samples are being processed to analyse the fungal diversity in each site. Mating-type and SSR genotyping on each collected fruit body is in progress and will be finished end of July 2015. Data of two sites were included in a large scale European population study that also revealed four genetics groups indicating the existence of T. aestivum ecotypes (Molinier et al, submitted to Mycorrhiza). However, from most of the sites no detailed site information was available to infer possible ecological differences of the observed ecotypes. Analysing these differences will be possible using the present sixteen monitoring
|
