Colonies of Tricholoma matsutake, which consist of fairy rings and the area they enclose, are called shiros in Japanese. We recently identified the antimicrobial substance at the active mycorrhizal zone, the shiro front, of T. matsutake as the (oxalato)aluminate complex. In the present study, seasonal changes in the content of the complex, the mycelial density of T. matsutake, antimicrobial activity, and pH were analyzed in the shiro area. Bacteria were isolated from the shiro area in October and identified, and their sensitivity to the complex was also examined. The change in the content of the complex approximately correlated with that of the mycelial density, and closely correlated with antimicrobial activity and pH. The bacteria from the shiro front were resistant to the complex, while some bacteria sensitive to the complex were found inside and outside the shiro front. This suggested that the complex expels sensitive bacteria from the shiro front along with the outward extension of the shiro, contributing to the protection and development of the shiro.

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Rhizopogon roseolus, a hypogeous basidiomycete, also known as “shoro” in Japan, is an important ectomycorrhizal symbiont of the Pinaceae. Recent studies suggest that ectomycorrhizal fungi play an important role in the protection of host roots from environmental stressors such as heavy metals and excessive salt. However, there are no studies characterizing salt tolerant strains of R. roseolus in a soil substrate. Here, we used sandy soil from the wild to observe the growth of R. roseolus strains in soil, and analyzed the correlation of mycelial growth between soil substrate and agar medium. All the strains grew well in sandy soil without a host plant, and on the surface of the soil, several hyphae aggregated to form a mycelial colony. A significant positive correlation was observed between the mycelial growth of R. roseolus in soil and on agar. In saline culture, mycelial growth in soil with 100% of the salinity of seawater showed a positive correlation with mycelial growth on 100% seawater agar medium. These results suggest that mycelia of R. roseolus seem more sensitive to salt in soil than on agar, and sandy soil will be useful to characterize the salt tolerance of R. roseolus strains in soil substrates.

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Clarification of risk in imported foods has led to raised awareness of consumers about food safety. Consequently, the retail and food-service industries treating mushrooms tend to focus on production information, including composition of the mushroom beds with value in domestic production. Pleurotus eryngii (DC.) Quél. is well known as a good edible mushroom in Japan. However, composition of the mushroom beds depends on imported raw materials. We considered domestic raw materials that can substitute for the bran from imported wheat frequently used in P. eryngii cultivation. Thus, meal from domestic and downgraded wheat as a potential material on the cost and supply side was identified from the refinement process and domestic distribution. Practical P. eryngii cultivation with this wheat meal indicated that the yield per bottle increased significantly, with an increase in available fruiting bodies.

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