Plants producing dust seeds often meet their carbon demands by exploiting fungi at the seedling stage. This germination strategy (i.e. mycoheterotrophic germination) has been investigated among orchidaceous and ericaceous plants exploiting Ascomycota or Basidiomycota. Although several other angiosperm lineages have evolved fully mycoheterotrophic relationships with Glomeromycota, the fungal identities involved in mycoheterotrophic germination remain largely unknown. Here, we conducted in situ seed baiting and high-throughput DNA barcoding to identify mycobionts associated with seedlings of Burmannia championii (Burmanniaceae: Dioscoreales) and Sciaphila megastyla (Triuridaceae: Pandanales), which have independently evolved full mycoheterotrophy. Subsequently, we revealed that both seedlings and adults in B. championii and S. megastyla predominantly associate with Glomeraceae. However, mycorrhizal communities are somewhat distinct between seedling and adult stages, particularly in S. megastyla. Notably, the dissimilarity of mycorrhizal communities between S. megastyla adult samples and S. megastyla seedling samples is significantly higher than that between B. championi adult samples and S. megastyla adult samples, based on some indices. This pattern is possibly due to both mycorrhizal shifts during ontogenetic development and convergent recruitment of cheating-susceptible fungi. The extensive fungal overlap in two unrelated mycoheterotrophic plants indicates that both species convergently exploit specific AM fungal phylotypes.

中文翻译：

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全异养植物的共生萌发和发育趋同于相似的球伞科类群

产生粉尘种子的植物通常通过在幼苗阶段利用真菌来满足其碳需求。已经在利用子囊菌门或担子菌门的兰科植物和石楠科植物中研究了这种发芽策略（即真菌异养发芽）。尽管其他几个被子植物谱系已经进化出与球囊菌门的完全异养关系，但与异养发芽有关的真菌身份仍然很大程度上未知。在这里，我们进行了原位种子诱饵和高通量 DNA 条形码编码，以鉴定与 Burmannia Championii (Burmanniaceae: Dioscoreales) 和 Sciaphila megastyla 幼苗相关的真菌生物（Triuridaceae：Pandanales），它们已经独立进化出完全的mycoheterotrophy。随后，我们揭示了B中的幼苗和成虫。Championii和S . megastyla主要与 Glomeraceae 相关。然而，菌根群落在幼苗期和成虫期之间有些不同，特别是在S。巨柱_ 值得注意的是， S之间菌根群落的差异。megastyla成虫样品和S . megastyla幼苗样品显着高于B . Championi成人样本和年代。megastyla成人样本，基于一些指数。这种模式可能是由于个体发育过程中菌根的变化和作弊敏感真菌的会聚募集。两种不相关的真菌异养植物中广泛的真菌重叠表明这两个物种都集中利用特定的 AM 真菌系统发育型。