The ecological significance of fungi occurring asymptomatically inside living plant leaves is poorly understood. Given the broad saprotrophic potential of many endophytic fungi, we hypothesized that they persist in decaying litter for an extended period of time after leaf abscission. Fungal assemblages were assessed by high-throughput sequencing in autumn leaves of beech (Fagus sylvatica) and in the corresponding leaf litter in 388 samples from 22 beech forest plots in three widely distant regions of Germany. A considerable proportion of the leaf-endophytic fungi was also found in 1-year-old litter. Co-occurrence networks revealed that the fungi formed unstructured assemblages inside the living leaves, rather than well-structured communities. Previously endophytic fungi constituted an integral part of the fungal litter community and were by far the most active fungi in 1-year-old litter. We therefore consider these endophytic occurrences to represent transient stages. Composition of the aboveground microbiome appears therefore to be closely connected to the process of litter decomposition. Considering the respective linked fungal habitat will facilitate predicting nutrient and carbon cycling and storage in forest ecosystems as well as elucidating the ecology of leaf microbiomes.

中文翻译：

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瞬时叶片内生菌是1岁山毛榉叶子凋落物中最活跃的真菌

人们对鲜活的植物叶片内无症状真菌的生态学意义了解甚少。考虑到许多内生真菌具有广泛的腐生潜能，我们假设它们在叶片脱落后在腐烂的凋落物中持续存在很长一段时间。通过高通量测序对山毛榉（Fagus sylvatica）的秋叶中的真菌组合进行评估），并在德国三个遥远地区的22个山毛榉林地的388个样本中的相应凋落物中进行调查。在1岁的幼仔中也发现了相当大比例的叶内生真菌。共生网络表明，真菌在活叶内部形成了非结构化的组合，而不是结构良好的社区。以前，内生真菌是真菌垫料群落不可分割的一部分，是迄今为止1岁垫料中最活跃的真菌。因此，我们认为这些内生事件代表了过渡阶段。因此，地上微生物组的组成似乎与垃圾分解过程密切相关。