Isovelleral, a volatile compound produced by some species of Russula and Lactarius, has various biological activities. However, the productivity of isovelleral in other species belonging to both genera has not been clarified. In this study, the contents of isovelleral in fruiting bodies of various russuloid fungi were investigated by UPLC-MS/MS. We confirmed that 32 species of Russula and 2 species of Lactarius contain isovelleral, and that among Russula, high productivity was phylogenetically restricted to Sect. Ingratae and Sect. Lactarioides. Isovelleral significantly inhibited the spore germination of Trichoderma spp. and Gliocladium spp. Therefore, isovelleral is thought to act as a defense factor against the invasion of mycoparasites into the fruiting body.

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The effectiveness of biological pretreatment by wood rot fungi for anaerobic methane fermentation from woody biomass was evaluated. Anaerobic fermentation was performed using co-culture of the cellulolytic acid- and hydrogen-producing anaerobic bacterium Clostridium thermocellum, and the methane-producing archaeon Methanothermobacter thermautotrophicus. For all of the fungi tested, four weeks of fungal pretreatment improved methane production from beech wood. Methane and hydrogen production varied among fungal treatments, and methane production was found to be dependent on the residual lignin content of the wood substrate. Among the fungi tested, the white rot fungus Phanerochaete sordida YK-624 showed the highest ligninolytic activity (33.2% of lignin removed) and methane production (5.9 mL/g pretreated beech wood). The fungus also improved methane production from cedar wood. Further, supplementation with 5% bran markedly increased methane production from beech and cedar wood substrates by 125% and 200%, respectively. The results suggested that methane production from fungal-pretreated wood was affected by the extent of delignification, and that optimizing the pretreatment conditions, such as the duration or the use of additives, is necessary for maximizing methane production.

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Coprinus comatus is an edible mushroom cultivated mainly in China and Korea. However, basic research of this mushroom species is limited. In this study, we considered the optimum pH, medium composition, and supplementation to promote spore germination with the aim of establishing a simple basidiospore isolation technique for C. comatus. Young hyaline spores lacking a germ pore and mature black spores having a germ pore were sampled from fruiting bodies cultivated and inoculated on each agar medium, adjusted to pH 3.0 to 9.0. As a result, spore germination of C. comatus was only observed in young spores. Optimum pH for both spore germination and mycelial growth was pH 6.0, indicating its utility for single spore isolation of C. comatus. Young spores germinated and generated mycelial growth in cow dung extract agar, but not in PDA and MA media. In addition, germination of young spores and subsequent colony formation were significantly stimulated by n-butyric acid supplementation (50 ppm final concentration). These results indicated that the use of young spores and cow dung extract agar medium, adjusted to pH 6.0 and supplemented with n-butyric acid, is valuable for basidiospore isolation of C. comatus.

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Shiitake (Lentinula edodes) is a cultivated edible mushroom species with medicinal properties. We investigated the inhibitory effect of shiitake methanol extract on biofilm formation by the periodontopathogenic bacterium Eikenella corrodens and the underlying mechanism. The extract inhibited biofilm formation by E. corrodens; extract obtained from the pileus part of new fresh shiitake especially had strong inhibitory effects. The biofilm-inhibitory effect was dose-dependent and was not due to bactericidal activity against E. corrodens; this effect was greater against the wild-type strain than the ΔluxS strain. The addition of the extract to E. corrodens culture medium significantly decreased autoinducer-2 production in the culture supernatant. The results suggest that the decrease in autoinducer-2 production by the shiitake methanol extract inhibited biofilm formation by E. corrodens.

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We investigated the efficacy of Beauberia bassiana against a Shiitake-pest mushroom fly, Neoempheria carinata, under laboratory conditions. First, we determined the survival rate of N. carinata adults exposed to two isolates of B. bassiana: F3231 from an adult cadaver of a N. carinata reared successively under laboratory conditions, and F263 from a larval cadaver of a longicorn beetle, Monochamus alternatus. Both B. bassiana isolates significantly decreased the survival rate of N. carinata adults at 4 and 5 days after treatment. Next, we investigated the efficacy of BIOLISA®-MADARA, a commercial biological control product containing B. bassiana F263 isolate, against N. carinata adults. We found that BIOLISA®-MADARA significantly shortened adult longevity, and decreased the number of eggs oviposited, but did not affect egg hatchability. These results indicate that BIOLISA®-MADARA and the isolates of B. bassiana F3231 and F263 were able to decrease numbers of subsequent generations of N. carinata by reducing total egg biomass.

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Tricholoma matsutake is an economically valuable fungus in Japan. However, its production is unpredictable because the fruiting bodies occur in natural forests and their development is affected by environmental conditions. Understanding these environmental conditions is essential for the sustainable production of T. matsutake fruiting bodies. Thus, to clarify the effect of environmental conditions on fruiting body development, we aimed to determine the ground temperature necessary for fruiting body initiation in T. matsutake. We observed fruiting body growth and ground temperature conditions in five colonies between 2001 and 2004 in a forest of a cold region. A logistic model was employed to determine the fruiting body growth of T. matsutake. Using this model, we determined the temperature for fruiting body initiation in T. matsutake to be approximately 15℃ at the study site. This value was lower than that observed in a warm region and suggests genetic adaptation of T. matsutake to a colder climate.

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