Mycoheterotrophic plants typically form associations with a narrow range of mycorrhizal fungi. Consequently, mycorrhizal specialization is often considered to be an important step in mycoheterotrophic evolution. However, it remains unclear whether such specialization is likely to occur in plants of the genus Pyrola, which are generally associated with fungi in multiple ectomycorrhizal families. Here, we investigated the mycorrhizal communities of a nearly fully mycoheterotrophic Pyrola species (Pyrola subaphylla), a closely related partially mycoheterotrophic Pyrola species (Pyrola japonica), and a co-occurring autotrophic ectomycorrhizal tree, Quercus crispula, which is their potential carbon source, in a cool-temperate Japanese forest. High-throughput DNA sequencing revealed that numerous common ectomycorrhizal OTUs interact with the two Pyrola species and Q. crispula, thereby providing an opportunity to exploit a certain amount of carbon from common mycorrhizal networks. In addition, not only P. japonica but also P. subaphylla exhibited exceptionally high alpha mycobiont diversity, with 52 ectomycorrhizal OTUs belonging to 12 families being identified as P. subaphylla mycobionts and 69 ectomycorrhizal OTUs in 18 families being detected as P. japonica mycobionts. Nonetheless, the beta mycobiont diversity of P. subaphylla and P. japonica individuals was significantly lower than that of Q. crispula. Moreover, the beta mycobiont diversity of P. subaphylla was found to be significantly lower than that of P. japonica. Therefore, despite their seemingly broad mycorrhizal interactions, the two Pyrola species (particularly P. subaphylla) showed consistent fungal associations, suggesting that mycorrhizal specialization may have developed during the course of mycoheterotrophic evolution within the genus Pyrola.

异养真菌的植物通常与狭窄的菌根真菌形成关联。因此，菌根特化通常被认为是菌异营养发展中的重要步骤。但是，尚不清楚这种专业化是否可能在Pyrola属植物中发生，这些植物通常与多个外生菌根家族的真菌有关。在这里，我们研究了几乎完全mycoheterotrophic的菌根社区鹿蹄类（鹿蹄subaphylla）密切相关的部分mycoheterotrophic鹿蹄类（鹿蹄粳稻）和共现自养外生菌根树，栎crispula是其在凉爽的日本森林中的潜在碳源。高通量DNA测序揭示许多常见外生菌根个OTU相互作用与两个鹿蹄草物种和Q. crispula，从而提供一个机会以利用一定量的从公共网络菌根碳。此外，不仅P.粳稻而且P. subaphylla表现出异常高的阿尔法mycobiont多样性，52菌根个OTU属于12个科被识别为P. subaphylla mycobionts和69个OTUs外生在被检测为18个家庭P.粳稻mycobionts 。尽管如此，公测mycobiont多样性P. subaphylla和龟纹瓢虫个体比的降低显著Q. crispula。此外，发现亚叶假单胞菌的β真菌生物多样性显着低于粳稻。因此，尽管他们看似广阔的菌根相互作用，两个鹿蹄类（特别是P. subaphylla）表现出一致的真菌协会，这表明菌根专业化可能mycoheterotrophic进化的属内的过程中，已经开发鹿蹄。