Summary Many plant species experience a prolonged subterranean phase during which they rely entirely on mycorrhizal fungi for carbon. While this mycoheterotrophic strategy spans liverworts, lycophytes, and ferns, most empirical research has centered on angiosperms. This study explores the fungal associations of Sceptridium (Ophioglossaceae), an early‐diverging fern with mycoheterotrophic gametophytes. We analyzed germination patterns and fungal associations in Sceptridium gametophytes, comparing them to the distribution and mycorrhizal partners of photosynthetic sporophytes. High‐throughput sequencing data reveal that mycoheterotrophic gametophytes consistently associate with a single Entrophospora fungus in the order Entrophosporales (Glomeromycotina), while photosynthetic sporophytes primarily partner with fungi from Glomeraceae (Glomerales, Glomeromycotina). Consequently, gametophytes exhibit spatial clustering without association with adult plants. This is the first documentation of an association between Entrophosporaceae (and the order Entrophosporales) and mycoheterotrophic plants. The drastic shifts in Sceptridium mycorrhizal communities across life stages likely reflect changing physiological needs during development. Further research is essential to determine whether the association with Entrophosporaceae is widespread among mycoheterotrophic species and to elucidate the functional and physiological mechanisms underlying these mycorrhizal shifts.

中文翻译：

---

在从完全菌种配子体到光合孢子体的世代转变过程中，Sceptridium 蕨类植物的菌根群落发生了剧烈的变化


摘要 许多植物物种经历了一个漫长的地下阶段，在此期间它们完全依赖菌根真菌获取碳。虽然这种真菌异养策略涵盖地钱、石松植物和蕨类植物，但大多数实证研究都集中在被子植物上。本研究探讨了 Sceptridium （Ophioglossaceae） 的真菌关联，Sceptridium 是一种早期分化的蕨类植物与真菌异养配子体。我们分析了 Sceptridium 配子体的发芽模式和真菌关联，将它们与光合孢子体的分布和菌根伙伴进行了比较。高通量测序数据显示，真菌异养配子体始终与 Entrophosporales （Glomeromycotina） 目中的单个 Entrophospora 真菌结合，而光合孢子体主要与来自 Glomeraceae （Glomerales， Glomeromycotina） 的真菌合作。因此，配子体表现出空间聚集，与成年植物无关。这是 Entrophosporaceae（和 Entrophosporales 目）与真菌异养植物之间关联的首次记录。菌根菌根群落在生命阶段的剧烈变化可能反映了发育过程中生理需求的变化。进一步的研究对于确定与内生孢子科的关联是否在菌根物种中广泛存在，并阐明这些菌根变化背后的功能和生理机制至关重要。