Center for Ecological Research, Kyoto University, Otsu, Shiga, 520-2113, Japan.
Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Kawaguchi, Saitama, 332-0012, Japan.
Microbiome. 2018 Jun 23;6(1):116. doi: 10.1186/s40168-018-0497-1.
Although a number of recent studies have uncovered remarkable diversity of microbes associated with plants, understanding and managing dynamics of plant microbiomes remain major scientific challenges. In this respect, network analytical methods have provided a basis for exploring "hub" microbial species, which potentially organize community-scale processes of plant-microbe interactions.
By compiling Illumina sequencing data of root-associated fungi in eight forest ecosystems across the Japanese Archipelago, we explored hubs within "metacommunity-scale" networks of plant-fungus associations. In total, the metadata included 8080 fungal operational taxonomic units (OTUs) detected from 227 local populations of 150 plant species/taxa.
Few fungal OTUs were common across all the eight forests. However, in each of the metacommunity-scale networks representing northern four localities or southern four localities, diverse mycorrhizal, endophytic, and pathogenic fungi were classified as "metacommunity hubs," which were detected from diverse host plant taxa throughout a climatic region. Specifically, Mortierella (Mortierellales), Cladophialophora (Chaetothyriales), Ilyonectria (Hypocreales), Pezicula (Helotiales), and Cadophora (incertae sedis) had broad geographic and host ranges across the northern (cool-temperate) region, while Saitozyma/Cryptococcus (Tremellales/Trichosporonales) and Mortierella as well as some arbuscular mycorrhizal fungi were placed at the central positions of the metacommunity-scale network representing warm-temperate and subtropical forests in southern Japan.
The network theoretical framework presented in this study will help us explore prospective fungi and bacteria, which have high potentials for agricultural application to diverse plant species within each climatic region. As some of those fungal taxa with broad geographic and host ranges have been known to promote the survival and growth of host plants, further studies elucidating their functional roles are awaited.
尽管最近的一些研究揭示了与植物相关的微生物的显著多样性，但理解和管理植物微生物组的动态仍然是主要的科学挑战。在这方面，网络分析方法为探索“枢纽”微生物物种提供了基础，这些物种可能组织社区规模的植物-微生物相互作用过程。
通过编译日本列岛 8 个森林生态系统中根系相关真菌的 Illumina 测序数据，我们探索了植物-真菌关联的“元社区规模”网络中的枢纽。总共有 8080 个真菌操作分类单元 (OTU) 是从 227 个 150 种/类植物的本地种群中检测到的。
很少有真菌 OTU 在所有 8 个森林中都很常见。然而，在代表北部四个地点或南部四个地点的每个元社区规模网络中，多样化的菌根、内生和病原真菌被归类为“元社区枢纽”，这些真菌从整个气候区的不同宿主植物类群中检测到。具体而言，Mortierella (Mortierellales)、Cladophialophora (Chaetothyriales)、Ilyonectria (Hypocreales)、Pezicula (Helotiales) 和 Cadophora (未分类) 在北部（冷温带）地区具有广泛的地理和宿主范围，而 Saitozyma/Cryptococcus (Tremellales/Trichosporonales) 和 Mortierella 以及一些丛枝菌根真菌则处于日本南部暖温带和亚热带森林元社区规模网络的中心位置。
本研究提出的网络理论框架将有助于我们探索具有高应用潜力的潜在真菌和细菌，这些真菌和细菌可应用于每个气候区的不同植物物种。由于一些具有广泛地理和宿主范围的真菌类群已被证明可以促进宿主植物的生存和生长，因此需要进一步研究来阐明它们的功能作用。
