Studies on entolomatoid fungi associated with rosaceous and ulmaceous plants in Japan and their utilization

Entolomatoid fungi associated with rosaceous and ulmaceous plants are known as edible mushrooms in Japan. In this paper, the author studied their host preference, taxonomy, mycorrhizal status and practical cultivation techniques with mycorrhizal seedlings as follows. 1) Field survey showed 17 plant species belonging to Rosaceae and Ulmaceae were hosts of the mushrooms. Among them, Pyracantha, Kerria (Rosaceae), and Zelkova (Ulmaceae) were newly reported as host plant's genera in this paper. 2) A morphological study demonstrated that the mushrooms so-called as 'Harushimeji' consisted of at least twelve types. Entoloma saepium and E. clypeatum f. hybridum in the types were newly recorded from Japan. 3) Stereoscopic microscopy of the mycorrhizas revealed that the fungal hyphae covered with root tips and formed unbranched mycorrhizas. Light microscopy revealed that root cap, apical meristem and cortex were disappeared and replaced by the fungal hyphae. Based on these results, it is proposed that they belong to a new type of mycorrhiza. 4) Transmission electron microscopy of the mycorrhizas suggested the destructive infection of the fungal hyphae to the root cells and their collapse near the tip of stele. 5) Mycorrhizas were observed notably in fruiting season of the mushrooms. 6) Availability of seedlings of host plants close to fruiting bodies and suspension of blended fruiting bodies were examined to cultivate the mushrooms with mycorrhizal seedlings. Seedlings of host plants close to mushroom formed this type of mycorrhiza. One year after transplanting and their mycorrhizas were observed in the root system, suggesting their potential availability to the mushroom cultivation. One year after pouring suspension, mycorrhizas were formed on roots of 20% inoculated plants in the shade but there was no statistical significance.