Mycorrhizal mushrooms form ectomycorrhiza on the root systems of woody host plants, such as Pinaceae and Fagaceae species, and include economically valuable edible mushrooms such as matsutake (Tricholoma matsutake) and truffle (Tuber melanosporum), as well as ecologically important species. Unlike saprotrophic mushrooms, it is difficult to obtain pure cultures of most mycorrhizal mushrooms as fungal resources for basal or applied studies, because their growth on artificial nutrient media is slow and often fails altogether. Thus, limited progress has been made in taxonomic and ecological investigations of this fungal group. In this study, taxonomy and ecology of mycorrhizal Amanita, Boletus, Tricholoma and Hygrophorus species were conducted, and cultivation techniques for those fungal taxa were established. Species examined in this study include valuable edible mushrooms such as Caesar’s mushrooms, porcini, matsutake, and yukishiro.

In this study, we placed the mycelial disks of six strains of hiratake grown on agar plates into a 40％ (w/w) glucose solution, used as a cryoprotectant, and incubated them at 7℃ or 25℃ for 0 (control)－24 h before freezing. The survival rates of two strains (ANCT-15001 and Po 89-1) were the highest when the discs had been incubated at 25℃ for 24 h and were 100％ even after storage at －20℃ for 10 wk. Although mycelial growth on PDA plates was delayed after cryopreservation for 10 wk, no change in fruiting ability of the two strains was observed.

To understand the habitat of Tricholoma matsutake in Hokkaido, we investigated the soil environment in an Abies sachalinensis plantation where this fungus colonized. As a result, soil pH and microbial quantity (colony forming unit; cfu) showed lower trend around the colony of T. matsutake than those areas where this fungus was not colonized. In addition, soil temperature was maintained over 0℃ even in the mid-winter despite the minimum air temperature recoded below −20℃, due to snow cover on the forest floor.