• The tree seed mycobiome has received little attention despite its potential role in forest regeneration and health. The aim of the present study was to analyze the processes shaping the composition of seed fungal communities in natural forests as seeds transition from the mother plant to the ground for establishment.
• We used metabarcoding approaches and confocal microscopy to analyze the fungal communities of seeds collected in the canopy and on the ground in four natural populations of sessile oak (Quercus petraea). Ecological processes shaping the seed mycobiome were inferred using joint species distribution models.
• Fungi were present in seed internal tissues, including the embryo. The seed mycobiome differed among oak populations and trees within the same population. Its composition was largely influenced by the mother, with weak significant environmental influences. The models also revealed several probable interactions among fungal pathogens and mycoparasites.
• Our results demonstrate that maternal effects, environmental filtering and biotic interactions all shape the seed mycobiome of sessile oak. They provide a starting point for future research aimed at understanding how maternal genes and environments interact to control the vertical transmission of fungal species that could then influence seed dispersal and germination, and seedling recruitment.

中文翻译：

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产妇效应塑造了栎栎的种子菌群

• 树种子菌群虽然在森林再生和健康中具有潜在作用，但几乎没有受到关注。本研究的目的是分析影响自然种子中种子真菌群落组成的过程，这些过程是种子从母体过渡到地面的过程。
• 我们使用metabarcoding方法和共聚焦显微镜分析了在四个无柄栎（Quercus petraea）自然种群的冠层和地面上收集的种子的真菌群落。使用联合物种分布模型推断了塑造种子菌群的生态过程。
• 真菌存在于种子内部组织，包括胚胎中。橡树种群和同一种群内的树木之间的种子菌群有所不同。它的成分在很大程度上受到母亲的影响，而对环境的影响很小。该模型还揭示了真菌病原体和真菌寄生虫之间可能存在的几种相互作用。
• 我们的结果表明，产妇效应，环境过滤作用和生物相互作用共同塑造了无柄橡树的种子菌群。它们为未来研究的起点，旨在了解母体基因和环境如何相互作用以控制真菌物种的垂直传播，从而可能影响种子的传播和发芽以及幼苗的募集。