High Species Diversity but Low Specificity to Ectomycorrhizal Tree Partners Exhibited by Native Truffle Species (Tuber spp., Pezizales) in Poland, Central Europe

Abstract

Truffles represent one of the most expensive edible fungi. About two-thirds of all known truffle records originate from Europe. Historically, the Mediterranean region in Southern Europe is associated with truffle cultivation and it is widely regarded as a center of truffle distribution in Europe. On the contrary, little is known about truffles in the central and northern regions of Europe. Here, native truffle species in Poland, their symbiotic ectomycorrhizal (ECM) tree partners, and their continental-scale distribution were studied. Altogether, 16 truffle species were identified based on the sequences of the Internal Transcribed Spacer (ITS) rDNA, a barcode region for fungi. Truffle species were associated with deciduous tree species of Fagales (Fagaceae, Betulaceae, Juglandaceae), Malvales (Malvaceae), Malpighiales (Salicaceae), and coniferous trees of Pinales (Pinaceae). Fagales trees constituted 70% of ECM associations formed by truffle species. Three genera of the order Fagales, Quercus, Fagus, and Corylus formed 50% of all ECM associations. Coniferous trees of Pinales formed 16% of associations. Two other orders of deciduous trees, Malvales and Malpighiales, together formed 14% of ECM associations. All but three identified truffle species exhibited low specificity to their ECM tree partners. Two-thirds of truffle species formed ECM symbiosis with both coniferous and deciduous tree species, but the share of coniferous tree partners was considerably lower than that of deciduous trees, reaching up to 30% for T. anniae, T. puberulum, and T. borchii (clade/puberulum). All the identified truffles were noted in both Central Europe and the Mediterranean region. Among them, about 80% of truffle species were widely distributed across the continent and represented by similar or higher numbers of records in Northern Europe, i.e., above the 48th parallel north, than in Southern Europe. This study showed higher taxa richness of native truffle species in Poland, but low specificity to their ECM tree partners. However, further studies on the regional-scale distribution of truffles in Poland are needed to improve the knowledge of the patterns of truffle distribution in forest ecosystems and the potential productivity of edible truffle species with high economic value.