Table_5_Structure and diversity of mycorrhizal fungi communities of different part of Bulbophyllum tianguii in three terrestrial environments.xlsx

Mycorrhizal fungi plays important roles in the seed germination and subsequent growth of orchids. The research of fungi in orchid roots, especially dominant mycorrhizal fungi is critical for orchids protection. In this study, the fungal community and composition of mycorrhizal fungi in roots, rhizomes and rhizosphere soil of Bulbophyllum tianguii grown in three terrestrial environments were analyzed by the second generation sequencing technology. The results of OTU clustering and α and β diversity analysis showed that there were significant differences in fungal communities in roots, rhizomes and rhizosphere soil of B. tianguii. The total number of OTUs in rhizomes was much less than that in roots and rhizosphere soil. The number of OTUs in rhizosphere soil and the diversity of mycorrhizal fungi were the highest. Meanwhile, the species and abundance of mycorrhizal fungi in roots and rhizomes of B. tianguii were different from those in rhizosphere soil. For different elevations, compared with B. tianguii that grow in middle of Tiankeng and top of Tiankeng, the OTUs number of B. tianguii in orchid garden is richest, and the diversity of mycorrhizal fungi in orchid garden was significantly higher than other locations. Among the three different habitats of B. tianguii, the number of OTUs in humus soil and stone habitats was notably higher than tree habitats, and the diversity of mycorrhizal fungi in humus soil was the highest. The analysis of mycorrhizal fungi in different habitats and altitudes of B. tianguii showed that Sebacina and Exophiala were the dominant mycorrhizal fungi in B. tianguii. The results of species annotation, phylogenetic tree and co-occurrence network analysis showed the dominant mycorrhizal fungi of B. tianguii mainly included Sebacina, Cladosporium, Exophiala, Fusarium. This study reveals the symbiotic relationship between Sebacina, Exophiala, Cladosporium and the B. Tianguii. It will provide a theoretical basis for the protection and biological function study of B. Tianguii.

丛枝菌根真菌在兰花的种子萌发及其后续生长过程中发挥着至关重要的作用。对兰花根系中真菌的研究，尤其是对优势丛枝菌根真菌的研究，对于兰花的保护至关重要。在本研究中，利用第二代测序技术，分析了生长于三种陆地环境中的蝴蝶兰天葵（Bulbophyllum tianguii）的根系、鳞茎及其根际土壤中的真菌群落及其组成。OTU聚类和α、β多样性分析结果显示，蝴蝶兰天葵的根系、鳞茎和根际土壤中的真菌群落存在显著差异。鳞茎中的OTU总数远低于根系和根际土壤。根际土壤中的OTU数量和丛枝菌根真菌的多样性最高。同时，蝴蝶兰天葵根系和鳞茎中的丛枝菌根真菌的物种和丰度与根际土壤中的不同。在不同海拔高度上，与生长在天坑中部的蝴蝶兰天葵相比，生长在山顶的蝴蝶兰天葵的OTU数量最为丰富，其根际土壤中的丛枝菌根真菌多样性显著高于其他地点。在蝴蝶兰天葵的三个不同生境中，腐殖土和石质生境中的OTU数量明显高于树质生境，腐殖土中的丛枝菌根真菌多样性最高。对蝴蝶兰天葵在不同生境和海拔高度上的丛枝菌根真菌分析表明，毛壳属（Sebacina）和毛霉属（Exophiala）是蝴蝶兰天葵中的优势丛枝菌根真菌。物种注释、系统发育树和共现网络分析的结果显示，蝴蝶兰天葵中的优势丛枝菌根真菌主要包括毛壳属、毛霉属、枝孢属（Cladosporium）和镰刀菌属（Fusarium）。本研究揭示了毛壳属、毛霉属、枝孢属与蝴蝶兰天葵之间的共生关系。研究结果将为蝴蝶兰天葵的保护和生物功能研究提供理论依据。