Truffle biogeography—A case study revealing ecological niche separation of different Tuber species

Abstract

Ecology of hypogeic mycorrhizal fungi, such as truffles, remains largely unknown, both in terms of their geographical distribution and their environmental niches. Occurrence of true truffles (Tuber spp.) was therefore screened using specific polymerase chain reaction (PCR) assays and subsequent PCR amplicon sequencing in tree roots collected at 322 field sites across the Czech Republic. These sites spanned a wide range of climatic and soil conditions. The sampling was a priori restricted to areas thought to be suitable for Tuber spp. inasmuch as they were characterized by weakly acidic to alkaline soils, warmer climate, and with tree species previously known to host true truffles. Eight operational taxonomic units (OTUs) corresponding to Tuber aestivum, T. borchii, T. foetidum, T. rufum, T. indicum, T. huidongense, T. dryophilum, and T. oligospermum were detected. Among these, T. borchii was the OTU encountered most frequently. It was detected at nearly 19% of the sites. Soil pH was the most important predictor of Tuber spp. distribution. Tuber borchii preferred weakly acidic soils, T. foetidum and T. rufum were most abundant in neutral soils, and T. huidongense was restricted to alkaline soils. Distribution of T. aestivum was mainly dictated by climate, with its range restricted to the warmest sites. Host preferences of the individual Tuber spp. were weak compared to soil and climatic predictors, with the notable exception that T. foetidum appeared to avoid oak trees. Our results open the way to better understanding truffle ecology and, through this new knowledge, also to better‐informed trufficulture.

High Fungal Diversity but Low Seasonal Dynamics and Ectomycorrhizal Abundance in a Mountain Beech Forest

“…Response curves to changes in pH and C org were linear, exponential or polynomic (Fig. 6 ), which reflects different subsections of unimodal response curves often described for environmental factors [e.g., 94 ]. A strong influence of soil pH, which directly affects availability of major nutrients and toxic elements, on soil microbial community composition has been repeatedly reported [e.g., 37 , 40 ].…”

Predicted climate change will increase the truffle cultivation potential in central Europe

“…Moreover, the few written documents from the early and mid twentieth century lack rigorous species identification nor do they provide sufficiently detailed information on the locations of truffle growth. Estimates of the potential truffle occurrence based on www.nature.com/scientificreports/ the detection of mycorrhiza in the roots of potential host trees were recently provided for the Czech Republic using a PCR screening method 56 . However, we cannot use these data for validation, since species-specific truffle primers for PCR detection are still associated with large uncertainties, and the presence of mycorrhiza alone does not automatically imply the production of fruiting bodies 57 .…”

The 287,403 bp Mitochondrial Genome of Ectomycorrhizal Fungus Tuber calosporum Reveals Intron Expansion, tRNA Loss, and Gene Rearrangement

“…Limited morphological features and overlapping of some features render it difficult to differentiate some Tuber species accurately. Reliable molecular markers are important tools for accurate identification and classification of Tuber species ( Fan et al, 2016 ; Gryndler et al, 2017 ; Qiao et al, 2018 ), also for understanding origin of Pezizales species. Mitochondrial genes have been widely used in phylogeny and population genetic study of animals, plants, and some classes of fungi ( Dai et al, 2018 ; Doyle et al, 2018 ; Li et al, 2019c ; Wang et al, 2020 ).…”