Mixotrophic plants obtain carbon by their own photosynthetic activity and from their root-associated mycorrhizal fungi. Mixotrophy is deemed a pre-adaptation for evolution of mycoheterotrophic nutrition, where plants fully depend on fungi and lose their photosynthetic activity. The aim of this study was to clarify mycorrhizal dependency and heterotrophy level in various phenotypes of mixotrophic Pyrola japonica (Ericaceae), encompassing green individuals, rare achlorophyllous variants (albinos) and a form with minute leaves, P. japonica f. subaphylla. These three phenotypes were collected in two Japanese forests. Phylogenetic analysis of both plants and mycorrhizal fungi was conducted based on DNA barcoding. Enrichment in ¹³C among organs (leaves, stems and roots) of the phenotypes with reference plants and fungal fruitbodies were compared by measuring stable carbon isotopic ratio. All plants were placed in the same clade, with f. subaphylla as a separate subclade. Leaf ¹³C abundances of albinos were congruent with a fully mycoheterotrophic nutrition, suggesting that green P. japonica leaves are 36.8% heterotrophic, while rhizomes are 74.0% heterotrophic. There were no significant differences in δ¹³C values among organs in both albino P. japonica and P. japonica f. subaphylla, suggesting full and high mycoheterotrophic nutrition, respectively. Among 55 molecular operational taxonomic units (OTUs) detected as symbionts, the genus Russula was the most abundant in each phenotype and its dominance was significantly higher in albino P. japonica and P. japonica f. subaphylla. Russula spp. detected in P. japonica f. subaphylla showed higher dissimilarity with other phenotypes. These results suggest that P. japonica sensu lato is prone to evolve mycoheterotrophic variants, in a process that changes its mycorrhizal preferences, especially towards the genus Russula for which this species has a marked preference.

混合营养植物通过自身的光合作用和根系相关的菌根真菌获得碳。混合营养被认为是菌异养营养进化的一种预适应方式，其中植物完全依赖真菌并失去其光合活性。这项研究的目的是澄清菌根依赖性和异养水平混养的各种表型鹿蹄粳稻（杜鹃花科），包含绿色个人稀有achlorophyllous变种（白化病），并用树叶分钟，窗体龟纹瓢虫F。亚叶。这三种表型是在两个日本森林中收集的。基于DNA条形码对植物和菌根真菌进行了系统发育分析。浓缩¹³通过测量稳定的碳同位素比，比较表型的器官（叶，茎和根）与参考植物和真菌子实体之间的碳。将所有植物与f置于相同的进化枝中。亚叶作为单独的子代。白化病叶片的¹³ C丰度与完全的真菌异养营养是一致的，这表明绿色的日本粳稻叶片具有36.8％的异养性，而根茎则具有74.0％的异养性。有在无δ差异显著^13个C值白化在这两个机构之间的龟纹瓢虫和龟纹瓢虫F。叶下，分别代表全营养和高营养。在共生的55个分子操作生物分类单位（OTU）中，Russula属在每种表型中含量最高，并且在白化病日本粳稻和粳稻f中的优势明显更高。亚叶。芸香属 在日本对虾中检测到f。亚叶与其他表型显示出更高的相似性。这些结果表明，日本假单胞菌在改变其菌根偏爱的过程中，特别是对红菇属的进化中，容易进化出菌异养型变体。 为此，该物种具有明显的偏爱。