Virtual Truffle Hunting—A New Method of Burgundy Truffle (Tuber aestivum Vittad.) Site Typing

Effects of Black and White Mulch on Mycelial Growth of Tuber Species in Korean Field Environment

Truffles, belonging to the genus Tuber, are ectomycorrhizal (ECM) fungi that form underground ascocarps and primarily establish symbiosis with oaks and hazels. The cultivation of Tuber spp. involves transplanting inoculated seedlings that have formed ectomycorrhiza with Tuber species, with mulching being effective for truffle cultivation. In this study, we investigated the effects of mulching on the mycelial growth of four Tuber species (T. himalayense, T. koreanum, T. melanosporum, and T. borchii) in the Korean natural environment, highlighting the potential for Korea as a truffle cultivation site. We developed and tested species-specific primers for quantifying the soil mycelial biomass of Tuber spp. by qRT-PCR, determined the superior mulch color for mycelial growth, and identified the Tuber species exhibiting the highest growth rate in the Korean field environment. Our results demonstrated that white mulch significantly enhanced mycelial growth in Tuber species than black mulch, likely owing to its ability to maintain low soil temperatures, control weeds, and improve host plant growth. Among the Tuber species, T. himalayense showed the greatest growth potential in the Korean natural environment. Additionally, a significant and positive correlation was observed between the mycelial biomass of Tuber species and the growth of inoculated seedlings, as measured by the total stem length and the number of leaves, thereby indicating the importance of symbiosis between ECM fungi and host plants. This study provides valuable insights into truffle cultivation in Korea and highlights the potential of using white mulch to promote mycelial growth, thereby contributing essential data for understanding the appropriate environmental conditions for Tuber spp. cultivation in Korea. Further study is needed to assess the long-term impact of mulching and to explore the effectiveness of other mulching materials.

Effect of Temperature, pH, and Media on the Mycelial Growth of Tuber koreanum

Members of the genus Tuber are ectomycorrhizal fungi; this genus includes more than 180 species worldwide. In the present study, the optimal pH, temperature, and medium suitable for the mycelial growth of the Korean truffle, Tuber koreanum, were determined. Mycelium of T. koreanum, isolated from fruiting bodies collected in Korea, was used to investigate the effects of these environmental factors. The results showed that malt extract agar and potato dextrose agar were the most suitable for the mycelial growth of T. koreanum when cultured at a pH of 6.0 at 25 °C for 30 days.

Ectomycorrhizal Assemblages of Invasive Quercus rubra L. and Non-Invasive Carya Nutt. Trees under Common Garden Conditions in Europe

Invasive tree species change biodiversity, nutrient cycles, and ecosystem services, and can turn native ecosystems into novel ecosystems determined by invaders. In the acclimatization and invasion of alien tree species, the crucial role is played by ectomycorrhizal (ECM) fungi. We tested ECM fungi associated with Quercus rubra and Carya trees that are alien to Europe. Quercus rubra is among the most invasive tree species in Europe, and the Carya species are not considered invasive. Both form ectomycorrhizal symbiosis, and in their native range in North America, coexist in oak-hickory forests. Six study stands were located in Kórnik Arboretum: three for Q. rubra and three for Carya trees. Ectomycorrhizal fungi were assessed by molecular identification of ECM roots. We identified 73 ECM fungal taxa of 23 ECM phylogenetic lineages. All identified ECM fungi were native to Europe. Similar richness but different composition of ECM taxa were found on Q. rubra and Carya roots. Phylogenetic lineages /tomentella-thelephora, /russula-lactarius, and /genea-humaria were most abundant on both Carya and Q. rubra roots. Lineages /tuber-helvella and /entoloma were abundant only on Carya, and lineages /pisolithus-scleroderma and /cortinarius were abundant only on Q. rubra roots. Analysis of similarities revealed a significant difference in ectomycorrhizal assemblages between invasive Q. rubra and non-invasive Carya. Highlights: (1) under common garden conditions, ECM taxa richness was similar on Q. rubra and Carya roots; (2) ECM taxa composition differed between invasive Q. rubra and non-invasive Carya; (3) high abundance of long-distance exploration type (lineages from Boletales) was on Q. rubra; and (4) high abundance of short-distance exploration type (e.g., /tuber-helvella) was on Carya.