Aoki Wataru, Endo Naoki, Hashimoto Yasushi, Tsuji Mimori, Ito Tesuro, Fukuda Masaki, Yamada Akiyoshi
Department of Agriculture, Graduate School of Science and Technology, Shinshu University, Minami-minowa, Nagano, 399-4598, Japan.
Division of Microbiology, National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki, Kanagawa, 210-9501, Japan.
Mycorrhiza. 2025 May 8;35(3):37. doi: 10.1007/s00572-025-01212-9.
Tricholoma kakishimeji, a poisonous fungus containing the toxic compound ustalic acid, has sometimes been misidentified as closely related species (T. stans, T. matsushimeji, T. kakishimejioides) under the name T. ustale in Japan until recently. Tricholoma ustale s. str. was not found in Japan according to a recent study, and it has been only recorded in Europe. Here, we report the first comprehensive morphological comparison of ectomycorrhizae among these four Tricholoma species. Several cultured strains of these species were inoculated onto Pinus densiflora in vitro. The resulting ectomycorrhizal pine seedlings were subsequently used as mother plants to establish an ectomycorrhizal system on Fagaceae plants. Although all tested fungal strains formed ectomycorrhizae on pine, mycorrhizal colonization by T. kakishimejioides was limited. On Quercus hosts, T. matsushimeji exhibited discontinuous Hartig net development, whereas T. kakishimeji and T. stans produced distinct Hartig nets. Additionally, ectomycorrhizal biomass development on oak hosts was limited in T. stans and T. matsushimeji. These findings correspond to the habitat characteristics of these fungal species. Ectomycorrhizae of these Tricholoma species sampled from natural forests showed morphological and anatomical characteristics similar to their in vitro ectomycorrhizae, including species-specific hyphal arrangements of the mantle and rhizomorphs. We propose that the ectomycorrhizal specificity of Tricholoma can be experimentally assessed in relation to their genetic background on pine and oak hosts, as well as the phyloecological characteristics of these fungal species.
松口蘑是一种含有有毒化合物乌斯他酸的有毒真菌，直到最近，在日本它有时仍会被误认作与之亲缘关系相近的物种（如硬柄口蘑、姬松茸、拟松口蘑），并以硬柄口蘑的名称出现。根据最近的一项研究，在日本未发现狭义的硬柄口蘑，它仅在欧洲有记录。在此，我们首次对这四种口蘑属物种的外生菌根进行了全面的形态学比较。将这些物种的多个培养菌株在体外接种到赤松上。随后，将由此产生的外生菌根化松树苗用作母株，在壳斗科植物上建立外生菌根系统。尽管所有测试的真菌菌株都能在松树上形成外生菌根，但拟松口蘑的菌根定殖有限。在栎属宿主上，姬松茸的哈氏网发育不连续，而松口蘑和硬柄口蘑则产生明显的哈氏网。此外，硬柄口蘑和姬松茸在栎属宿主上的外生菌根生物量发育有限。这些发现与这些真菌物种的栖息地特征相符。从天然森林中采集的这些口蘑属物种的外生菌根在形态和解剖学特征上与其体外外生菌根相似，包括菌套和菌索中物种特异性的菌丝排列。我们建议，可以通过实验评估口蘑属在外生菌根特异性方面与其在松树和栎属宿主上的遗传背景以及这些真菌物种的系统生态特征之间的关系。
