Data_Sheet_1_Dominant Dendrobium officinale mycorrhizal partners vary among habitats and strongly induce seed germination in vitro.pdf

Dendrobium officinale (Orchidaceae) is an endangered epiphytic orchid that has been well studied as a medicinal plant. Although previous studies have shown that various fungal isolates promote D. officinale seed germination and seedling development in vitro, mycorrhizal associations among its wild populations remain poorly understood. In this study, we identified mycorrhizal fungi associated with D. officinale (36 individuals from six sites) using Sanger sequencing and compared fungal communities among sites and habitats (lithophytic vs. epiphytic individuals). Among the obtained sequences, 76 belonged to orchid mycorrhizal fungi (OMF), among which Tulasnellaceae accounted for 45.8% and Serendipitaceae for 28.1%. The Serendipitaceae operational taxonomic unit (OTU) SE1 was the most dominant partner, accounting for 27.1% of all detected fungal sequences, followed by a Tulasnellaceae OTU, TU27, which accounted for 15.6%. The relative frequencies of Serendipitaceae and Tulasnellaceae differed greatly between lithophytic and epiphytic individuals. Serendipitaceae accounted for 47.3% of the OMF sequences among lithophytes, and Tulasnellaceae for 95.2% among epiphytes. Mycorrhizal community composition also varied among sites. We further conducted in vitro symbiotic culture from seeds with six fungal isolates. Two Serendipitaceae and two Tulasnellaceae isolates, including SE1 and TU27, significantly promoted seed germination and seedling development. These results indicate that D. officinale is mainly associated with Tulasnellaceae and Serendipitaceae as its main fungal partners, which strongly induced seed germination and seedling development in vitro, suggesting their association with D. officinale through its life cycle.

Dendrobium officinale，属兰科（Orchidaceae）的一种濒危附生兰花，作为药用植物已得到广泛研究。尽管先前的研究表明，多种真菌分离株可促进D. officinale的种子在体外萌发和幼苗生长，但其野生种群中的菌根联合关系仍鲜为人知。在本研究中，我们采用Sanger测序技术，确定了与D. officinale相关的菌根真菌（来自六个地点的36个个体），并比较了不同地点和生境（石生与附生个体）之间的真菌群落。在获得的序列中，76个属于兰科菌根真菌（OMF），其中Tulasnellaceae占45.8%，Serendipitaceae占28.1%。Serendipitaceae操作分类单元（OTU）SE1是最主要的共生伙伴，占所有检测到的真菌序列的27.1%，其次是Tulasnellaceae OTU TU27，占15.6%。Serendipitaceae和Tulasnellaceae的相对频率在石生和附生个体之间存在显著差异。在石生个体中，Serendipitaceae占OMF序列的47.3%，而在附生个体中，Tulasnellaceae占95.2%。菌根群落组成在不同地点之间也存在差异。我们进一步从种子中采用六种真菌分离株进行了体外共生培养。其中两个Serendipitaceae和两个Tulasnellaceae分离株，包括SE1和TU27，显著促进了种子萌发和幼苗生长。这些结果指示D. officinale主要与Tulasnellaceae和Serendipitaceae作为其主要真菌伙伴相联合，这些真菌在体外强烈诱导种子萌发和幼苗生长，暗示它们通过与D. officinale的生命周期相联系。