Vaario Lu-Min, Pennanen Taina, Lu Jinrong, Palmén Jorma, Stenman Jarkko, Leveinen Jussi, Kilpeläinen Petri, Kitunen Veikko
Finnish Forest Research Institute, PL 18, 01301, Vantaa, Finland,
Mycorrhiza. 2015 Jul;25(5):325-34. doi: 10.1007/s00572-014-0615-2. Epub 2014 Oct 30.
Tricholoma matsutake, a highly valued delicacy in Japan and East Asia, is an ectomycorrhizal fungus typically found in a complex soil community of mycorrhizae, soil microbes, and host-tree roots referred to as the shiro in Japan. A curious characteristic of the shiro is an assortment of small rock fragments that have been implicated as a direct source of minerals and trace elements for the fungus. In this study, we measured the mineral content of 14 samples of shiro soil containing live matsutake mycelium and the extent to which the fungus can absorb minerals directly from the rock fragments. X-ray powder diffraction identified major phases of quartz, microcline, orthoclase, and albite in all shiro samples. PCR-denaturing gradient gel electrophoresis (DGGE) fingerprinting and direct sequencing confirmed the presence of T. matsutake on 32 of 33 rock fragments. Piloderma sp. co-occurred on 40% of fragments and was positively correlated with locations known to produce good mushroom crops. The ability of T. matsutake to absorb trace elements directly from rock fragments was examined in vitro on nutrient-agar plates supplemented with rock fragments from the shiro. In comparison to the mineral content of tissues grown on control media, the concentration of Al, Cu, Fe, Mn, P, and Zn increased from 1.1 to 106.4 times for both T. matsutake and Piloderma sp. Mineral content of dried sporocarps sampled from the study site partially reflected the results of the in vitro study. We discuss the implications of our results with respect to the natural development and artificial culture of this important fungus.
松口蘑是日本和东亚地区备受珍视的美味佳肴，它是一种外生菌根真菌，通常生长在由菌根、土壤微生物和宿主树根组成的复杂土壤群落中，在日本被称为“菌塘”。菌塘的一个奇特特征是含有各种小岩石碎片，这些碎片被认为是该真菌矿物质和微量元素的直接来源。在本研究中，我们测量了14个含有活松口蘑菌丝体的菌塘土壤样本的矿物质含量，以及该真菌直接从岩石碎片中吸收矿物质的程度。X射线粉末衍射确定了所有菌塘样本中的主要物相为石英、微斜长石、正长石和钠长石。PCR-变性梯度凝胶电泳（DGGE）指纹图谱和直接测序证实，33个岩石碎片中有32个存在松口蘑。皮氏菌在40%的碎片上与松口蘑共生，并且与已知能产出优质蘑菇的地点呈正相关。在添加了来自菌塘的岩石碎片的营养琼脂平板上，体外检测了松口蘑直接从岩石碎片中吸收微量元素的能力。与在对照培养基上生长的组织的矿物质含量相比，松口蘑和皮氏菌中铝、铜、铁、锰、磷和锌的浓度增加了1.1至106.4倍。从研究地点采集的干燥子实体的矿物质含量部分反映了体外研究的结果。我们讨论了这些结果对这种重要真菌自然发育和人工栽培的意义。
