AUTHOR=Park Ki Hyeong , Oh Seung-Yoon , Yoo Shinnam , Park Myung Soo , Fong Jonathan J. , Lim Young Woon 

TITLE=Successional Change of the Fungal Microbiome Pine Seedling Roots Inoculated With Tricholoma matsutake

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.574146

DOI=10.3389/fmicb.2020.574146

ISSN=1664-302X

ABSTRACT=<p>The pine mushroom (<italic>Tricholoma matsutake</italic>; Agaricales, Tricholomataceae) is an ectomycorrhizal fungus that produces a commercially valuable, edible mushrooms. Attempts to artificially cultivate <italic>T. matsutake</italic> has so far been unsuccessful. One method used to induce <italic>T. matsutake</italic> to produce fruiting bodies of in the wild is shiro (mycelial aggregations of <italic>T. matsutake</italic>) transplantation. <italic>In vitro</italic> ectomycorrhization of <italic>T. matsutake</italic> with seedlings of <italic>Pinus densiflora</italic> has been successful, but field trials showed limited production of fruiting bodies. Few studies have been done to test what happens after transplantation in the wild, whether <italic>T. matsutake</italic> persists on the pine seedling roots or gets replaced by other fungi. Here, we investigated the composition and the interaction of the root fungal microbiome of <italic>P. densiflora</italic> seedlings inoculated with <italic>T. matsutake</italic> over a 3 year period after field transplantation, using high-throughput sequencing. We found a decline of <italic>T. matsutake</italic> colonization on pine roots and succession of mycorrhizal fungi as <italic>P. densiflora</italic> seedlings grew. Early on, roots were colonized by fast-growing, saprotrophic Ascomycota, then later replaced by early stage ectomycorrhiza such as <italic>Wilcoxina</italic>. At the end, more competitive <italic>Suillus</italic> species dominated the host roots. Most of the major OTUs had negative or neutral correlation with <italic>T. matsutake</italic>, but several saprotrophic/plant pathogenic/mycoparasitic species in genera <italic>Fusarium</italic>, <italic>Oidiodendron</italic>, and <italic>Trichoderma</italic> had positive correlation with <italic>T. matsutake</italic>. Four keystone species were identified during succession; two species (<italic>Fusarium oxysporum</italic>, and <italic>F. trincintum</italic>) had a positive correlation with <italic>T. matsutake</italic>, while the other two had a negative correlation (<italic>Suillus granulatus</italic>, <italic>Cylindrocarpon pauciseptatum</italic>). These findings have important implications for further studies on the artificial cultivation of <italic>T. matsutake</italic>.</p>