New information from a survey of truffles carried out in southern part of Poland in September 2007 is presented. The fruit bodies of Tuber aestivum, T. excavatum, T. rufum and one unidentified Tuber sp. were found. The soil chemistry of the five T. aestivum sites was analysed. Our inventory showed that T. aestivum prefers the mixed forest with host-trees such as: Quercus robur, Corylus avellana, Carpinus betulus, Fagus silvaticus and Tilia cordata. Selection of local inocula of T. aestivum for the propagation of truffles production could be an alternative to the Mediterranean truffles orchards in times when demand for the fungi will be increasing. Fruit bodies of truffles are conserved in the collection of biological material in the Forest Research Institute in Sekocin Stary.

We describe the ectomycorrhizal (ECM) root tips and the diversity of mycorrhizal fungal species at three English oak (Quercus robur) sites (two 120 year old sites and one 60 year old site). The three oak stands in decline, located in western Poland, were characterized by a low degree of vital ECM colonization: 30.2%, 29.1% and 25.6% at Krotoszyn (K), Piaski (P) and Karczma Borowa (KB), respectively. DNA (ITS) barcoding revealed a total of 18 ECM fungal species. Based on exploration types, ectomycorrhizae were classified with respect to ecologically relevant features. The contact type was significantly correlated with C:N and Corg, while the short distance type was correlated with Ca, phosphorus (P2O5) and pH. The medium distance exploration type was significantly correlated with fine-grained soil particle size fractions: coarse silt (0.05–0.02 mm) and fine silt (0.02–0.002 mm), and clay (<0.002 mm). The long distance type showed a similar pattern to the medium distance smooth type, but was also correlated with nitrate (N). The values of biometric root parameters of oak trees at the analysed forest sites were arranged as follows: K > P > KB, and were opposite to the condition of the tree crowns. A negative correlation of vital ECM root tip abundance with the crown health status of oaks was observed, whereas higher ECM diversity reflected better crown health in the oak stands studied.

Tuber species may be regarded as complex microhabitats hosting diverse microorganisms inside their fruiting bodies. Here, we investigated the structure of microbial communities inhabiting the gleba of wild growing (in stands) T. aestivum, using Illumina sequencing and culture-based methods. The two methods used in combination allowed to extract more information on complex microbiota of Tuber aestivum gleba. Analysis of the V3–V4 region of 16S rDNA identified nine phyla of bacteria present in the gleba of T. aestivum ascomata, mostly Proteobacteria from the family Bradyrhizobiaceae. Our results ideally match the earlier data for other Tuber species where the family Bradyrhizobiaceae was the most represented. The ITS1 region of fungal rDNA represented six alien fungal species belonging to three phyla. To complement the metagenomic analysis, cultivable fungi and bacteria were obtained from the gleba of the same T. aestivum fruiting bodies. The identified fungi mostly belong to the phylum Basidiomycota and same to Ascomycota. Analysis of cultivable bacteria revealed that all the specimens were colonized by different strains of Bacillus. Fungal community inhabiting T. aestivum fruiting bodies was never shown before.

AbstractThis paper describes the quantitative and qualitative composition of bacteria isolated from soil in the selected sites in the Nida Basin, in places where mycorrhizae and ascocarps of summer truffle (Tuber aestivum) were found, and in a control soil (without truffle). A classic growth culture method was used with Sanger DNA sequencing to obtain quantitative and qualitative measures of bacterial cultures. The obtained results showed differences in bacteriome composition between the case samples, in which summer truffle fructification was observed, and the control samples. Seven classes of bacteria were identified: Actinobacteria, Bacilli, Deinococci, Flavobacteria, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. The most numerous bacterial genera were Pseudomonas (class Gammaproteobacteria) – 33%, Streptomyces (class Actinobacteria) – 29% and Bacillus (class Bacilli) – 15%. This research broadens the understanding of individual groups of bacteria accompanying truffles and their potential impact on the formation of summer truffle ascocarps.

Fungi belonging to the genus <em>Tuber</em> establish ectomycorrhizal symbioses with shrubs, trees and some herbaceous plants. Some <em>Tuber</em> species, for example, <em>T. melanosporum</em>, <em>T. magnatum</em>, <em>T. aestivum</em> are economically important because they produce edible fruiting bodies with a distinctive taste and flavor. Our concept of truffle ecophysiology is dominated by the symbiosis with deciduous hosts, such as: <em>Quercus</em> spp., <em>Fagus sylvatica</em>, <em>Castanea sativa</em>, <em>Corylus</em> spp., <em>Carpinus betulus</em>, <em>Ostrya carpinifolia</em>, <em>Betula verrucosa</em>, and <em>Tilia</em> spp., whereas the real range of hosts in nature seems to be much wider. Moreover, interactions between <em>Tuber</em> mycelium and plant community could be more complex than just forming the ectomycorrhizal symbiosis. Here we show our inventory of plants and soils at six truffle’ sites in the southern part of Poland (Nida Basin and Przedbórz Upland). The aim of this study was to widen our understanding of ecological factors affecting <em>Tuber</em> spp., in the context of pioneering stage of research on truffles in Poland. We hope our findings will have a practical application and will help to choose suitable soils for truffle orchards.