A recent study revealed that three Bacillus strains isolated from mushroom hyphae stimulated the mycelial growth of ectomycorrhizal (ECM) mushroom strains. In this study, we examined the factors influencing the mycelial growth of ECM mushroom strains using four culture methods: non-contact, bi-plate, spent broth and cell-contact cultures. The relative growth of ECM mushrooms increased when we used the three culture methods (non-contact, bi-plate and spent broth cultures). However, when using cell-contact culture, the bacteria exhibited variable effects, including significant inhibition and stimulation. Significant inhibition of mycelial growth was constantly observed in the co-culture between Bacillus tequilensis MBRr6a and all ECM mushroom strains, ranging from complete inhibition (0.00%) to 67.2%. When B. subtilis MBRr6b and B. pseudomycoides MBSg7b were co-cultured directly with their host mushroom strains, mycelial growth was inhibited, and the relative growth rate was decreased to 76.1% and 56.2%, respectively. When bacterial strains were co-cultured directly with non-host ECM mushrooms, mycelial growth was remarkably stimulated. These results suggest that the key factors influencing the mycelial growth of ECM mushrooms were related not only to water-soluble and volatile metabolites but also to the cell contact with hyphal bacteria. Furthermore, this indicates that the effect was dependent on the bacterial and ECM mushroom strains. Key words: Ectomycorrhizal mushroom, Hyphal bacteria, Physical contact, Volatile metabolite, Water-soluble metabolite

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シイタケ菌床栽培における作業の省力化を目指し，浸水を必要としない散水や注水により菌床の水分を制御して子実体発生面を限定する栽培技術を開発するために，トレーに充填した培地で培養および発生管理を行い，菌床内部への注水と菌床表面への散水による上面発生を検討した．慣行区（C区）で発生管理前半の収量増加が顕著だった一方で，トレー栽培では発生時期が分散した．これらのうち注水処理区のWI区は後半にC区と同程度の発生収量に到達した．また，個体重はC区比1.4～1.6倍となったことから，子実体のサイズ向上による品質向上だけでなく，収穫個数減少による省力化に寄与する可能性を見出した．次に注水および散水操作の効率化を図るため，各種器具の利用を検討した結果，各試験区の子実体収量および個体重に大きな違いは見られなかったことから，各操作の効率化を図りながら収穫の省力化が可能である．

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The effective use of Rhizopogon roseolus basidiospores in year-round crossbreeding programs largely depends on developing practical preservation methods that maintain their germination potential. Here, we assessed the germination capacity of this mushroom on 1 / 5 diluted modified Melin-Norkrans agar media following various storage conditions, including water suspension at 5℃ and -20℃, and preservation within frozen and dried tissues. Under optimal preservation conditions, we further examined the relationship between basidiospore maturity and preservation efficacy using basidiospores with low, medium, and high initial germination rates. While germination rates declined from fresh states, basidiospores preserved in water suspension at 5℃ for 6 months showed higher germination than the other preservation conditions. After 12 months in water suspension at 5℃, basidiospores of all maturity stages remained viable, forming colonies on 1 / 5 diluted modified Melin-Norkrans agar media. Notably, those with high initial germination rates retained higher germination than other stages. These results suggest that selecting R. roseolus fruiting bodies with basidiospores showing high germination potential before preservation in water suspension at 5℃ can enhance homokaryon production. This highlights the practical use of preserved R. roseolus basidiospores as inoculum in year-round crossbreeding programs. Key words: Basidiospore germination, Crossbreeding, Ectomycorrhizal fungi, Mycelial colony, Nutrient agar medium

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きのこ栽培において，ソバ殻の利用が求められているが，ソバアレルゲンの子実体への移行の懸念から，きのこ栽培の培地への添加が進んでいない．そこで本研究では，ソバ殻を添加した培地で栽培したマイタケ子実体に，ソバタンパク質が移行するかどうかを検討した．その結果，菌床からはソバタンパク質が検出できたが，子実体におけるソバタンパク質量は，検出限界以下であった．以上のことより，ソバ殻を子実体栽培に利用することにより，マイタケ子実体がソバアレルゲンに汚染される可能性は，かなり低いことが証明できた．

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本研究では，エノキタケ（白エノキおよび茶エノキ）の組織構造と破断強度に関する解析を行い，菌糸の密度や配向がその力学特性に影響を与えている可能性を明らかにした．2種のエノキタケの構造的違いが，食感の違いに関連していると推測される．また，エノキタケの柄には中央に中空構造が存在し，これが軽量かつ強度を保つ上で重要な役割を果たすことが示唆された．これらの特徴は，エノキタケをバイオベース材料として活用する可能性を広げると期待される．例えば，中空構造を活かした軽量で強度のある緩衝材や梱包材の応用，菌糸の配向性を活かした紙やフィルム状成形体の強度向上が見込まれる．さらに，白エノキと茶エノキの構造特性の違いから，用途に応じた機能性設計が可能であり，持続可能な素材としての展開が期待される．食品分野にも応用可能性があり，食感設計においてエノキタケの有用性が期待される.

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