To promote the production of edible mushrooms in Satoyama areas, this study examined the development of mushroom cultivation techniques and cultivars. The major achievements resulting from this research were as follows. 1. A simple inoculation method for bed-log cultivation using spawn comprising disposable chopsticks and toothpicks was devised and demonstrated for Kuritake (Hypholoma lateritium) cultivation. These methods were patented as a “mushroom inoculation method”. 2. In Kuritake mushrooms, high levels of mitochondrial DNA (mtDNA) variability may be maintained in natural populations. 3. Kuritake mycelia grow and spread in the soil using woody residues as a substrate while developing hyphal cords and rhizomorphs. In addition, a method for culturing Kuritake mycelia in nature on sterilized logs was developed. Specifically, a buried culture-bed method employing a basic knowledge of Kuritake cultivation was used in this study. 4. Mushroom genetic resources collected from wild mushrooms, such as Nameko (Pholiota microspora, Numerisugitake (Pholiota adipose), Yamabushitake (Hericium erinaceus), and Kuritake were used to improve cultivars used in mushroom production.

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Mycoleptodonoides aitchisonii is a wood-rooting edible mushroom. In response to previous reports that some basidiospore isolates of this mushroom can form complete fruiting bodies and true clamp cells, the frequency of true clamp cell formation was compared between the dikaryotic and the monokaryotic strains. Compared to monokaryotic strains, true clamp cells were observed with greater frequency in dikaryotic strains. Mating incompatibility groups were examined among basidiospore isolates from dikaryotic strain TUFC50005 (P) and TUFC50005-7 × TUFC50005-18 (F1), which were derived from strain TUFC50005. Mating compatibility could be divided into two groups indicating that M. aitchisonii is a bipolar mushroom. Moreover, recombinant mating type strain might not be generated after meiosis, indicating that there may only be a single mating-type locus in M. aitchisonii. No genetic linkage was observed between the phenotype capable of forming monokaryotic clamp cells and mating type, indicating that monokaryotic clamp formation was not linked to the mating-type locus.

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Rhizopogon roseolus (Corda) Th. M. Fr. is an edible ectomycorrhizal mushroom. Bacterial strains promoting the development of mycorrhizal symbiosis have been frequently isolated from mycorrhizospheres. Recently, we isolated certain bacteria from fruiting bodies of R. roseolus and observed that the bacteria could stimulate mycelial growth. In this study, we isolated various bacteria from fruiting bodies and investigated their effect on mycelial growth of R. roseolus using a co-culture method. Among nineteen cultivable bacterial strains from the fruiting body of R. roseolus, six bacterial strains specifically stimulated the mycelial growth of R. roseolus. Blast analysis revealed that the bacterial strains belonged to the genera Paraburkholderia, Caballeronia, Janthinobacterium, Novosphingobium and Rhodobacter. Ultrastructure morphologies of the dominant three strains were revealed by scanning electron microscopic observation. These results indicate the possible involvement of specific bacteria on fruiting body formation of R. roseolus.

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Polyporus ciliatus (Polyporales, Basidiomycota) is reported as a new record to Japan with a new Japanese name (“Ezono-amisugi-take”) based on both morphological and phylogenetic analyses of specimens from Hokkaido. Phylogenetic analyses revealed that P. ciliatus collections from Japan, China and Denmark had identical nuclear large ribosomal subunit sequences and formed a distinct clade with P. longiporus. Examinations of cultural characters revealed that P. ciliatus produce subglobose to fusiform, rarely clavate chlamydospores. We also re-evaluated the holotype of P. saitoi collected from Japan. Polyporus saitoi has been treated as a synonym of P. ciliatus, but the holotype has corky context, a reddish-brown pileus surface when dry, and larger pores [(3-) 4-5 pores/mm] than P. ciliatus, and it is morphologically distinct from P. ciliatus. We conclude that the status of P. saitoi as a valid species is dubious name because the holotype lacks microscopic characters besides skeletal-binding hyphae which are insufficient for species identification.

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