We analysed nucleotide sequences of phenol oxidase genes in Pholiota microspora and identified three types of phenol oxidase: laccase (Lcc1-Lcc8), ferroxidase (Lcc9), and tyrosinase (Tyr). The expression of Lcc1 to Lcc9 and Tyr genes in P. microspora was examined by qRT-PCR. We quantified transcripts of these ten genes in mycelia, primordia, and fruiting bodies grown on sawdust substrate and in mycelia grown in M4 liquid medium supplemented with aromatic compounds. All Lcc genes were expressed at a very low level in mycelia grown on sawdust medium, but Lcc1 was transcribed at a level 8-fold higher in M4 liquid medium when supplemented with 3 mM veratryl alcohol. On the other hand, Lcc9 and tyrosinase were highly expressed in primordia and fruiting bodies. These results suggest that the content of melanin and related pigments in the fruiting body might be determined by complementary activity of two types of phenol oxidase, such as Lcc and Tyr, in P. microspora.

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In this study, we identified five manganese peroxidase genes (PnMnPs) in the Pholiota microspora haploid genome. Their amino acid sequences showed high similarity and were used to construct a phylogenetic tree. PnMnP5, 3, 2 and 4 were clustered tightly, but PnMnP1 was clustered relatively far from PnMnP5. qRT-PCR showed that PnMnP5 was the only MnP gene that was strongly transcribed, showing 15-fold higher expression than other PnMnPs in M4 liquid medium, while transcription of PnMnP5 in sawdust medium was 100 times higher than in M4 liquid medium. These results indicate that PnMnP5 plays a major role in the ligninolytic peroxidase reaction during mycelial growth in P. microspora. Based on a comparison of the position of introns, the phylogenetic relationships among PnMnPs and the predominant expression of PnMnP5, we believe that all PnMnPs are of the same origin and that they were amplified by duplication events in the ancient P. microspora genome.

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Brown rot disease of shiitake mushrooms, Lentinula edodes, cultivated on bed logs was found in two identified locations of natural fruiting yards in Oita Prefecture during 2013-2014. Bed logs containing fruiting shiitake mushrooms with brown rot symptoms were transferred to and managed at a research center. We could reproduce the same symptoms on newly fruiting shiitake mushrooms in the following year. Brown rot symptoms were also observed on mating strains of shiitake mushrooms grown at an artificial fruiting yard in the research center. A-D3 selective medium was used to isolate the causative bacterium; yellow colonies with white margins grew on the medium. The causative bacterium was isolated from the surface of bed logs as well as brown rotting fruit bodies of L.edodes. 16S rRNA gene analysis of the isolates was conducted and the bacterium was identified as Ewingella americana. Further, young fruit bodies of shiitake mushrooms on sawdust medium were injected with the isolated bacterium from brown rotting fruit bodies of L.edodes and the surface of bed logs. Consequently, the mushrooms showed rotting symptoms after 5 days, so we are able to establish a method to identify the pathogenicity of isolated bacterium effectively.

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To evaluate the effects of Agaricus spent compost(ASC) on crop productivity and the soil environment, we cultivated "Momiroman", a new high-yielding rice cultivar for feed use, in a rice paddy amended with 2 t/10 a ASC. The number of bacteria, actinomycetes, and filamentous fungi increased. In particular, the proportion of actinomycetes was markedly increased in the ASC-treated paddy soil. Soil hardness, humic content, and inorganic nitrogen were also significantly higher in ASC-treated rice paddy fields than those of the control soil. However, the cation exchange capacity and total exchangeable bases were not affected by ASC treatment. Plant height, culm length, ear length, number of ears per plant, grain weight, and total crop weight of rice plants grown in ASC-treated soil were higher than those of the untreated control group. Total crop weight was 1495 kg/10 a for the control group and 1716 kg/10 a for the ASC group, representing a 14.8% increase. With regard to internal quality, the branched-chain amino acids, isoleucine, leucine and valine were increased. These findings indicate the application of ASC to rice paddy field soil is effective to the productivity and quality of the rice crop.

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Spawn is the vegetative mycelium of mushroom grown on various convenient media. Addition of several kinds of grain to increase viability of mycelium in spawn is an important point in mushroom cultivation. The aim of this study is to reveal the optimum addition of sorghum to sawdust spawn of Pleurotus ostreatus. The results showed that the spawn containing 30% sorghum was most favorable to mycelium growth. The mycelium grew to 88.8 mm after 9 days and 139.2 mm after 18 days of incubation. On the other hand, spawn supplemented with 40% sorghum gave the highest formation of fruiting bodies, 351.3 g. The results also indicated that diameter of caps and length of stipe of P. ostreatus were not affected by growth of mycelium on the substrate.

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