School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, 08826, South Korea.
Mycorrhiza. 2022 Nov;32(5-6):439-449. doi: 10.1007/s00572-022-01088-z. Epub 2022 Jul 21.
Ectomycorrhizal fungi (EMF) form symbiotic relationship with the roots of host plants. EMF communities are composed of highly diverse species; however, how they are assembled has been a long-standing question. In this study, we investigated from a phylogenetic perspective how EMF communities assemble on Pinus densiflora seedlings at different spatial scales (i.e., seedling scale and root tip scale). P. densiflora seedlings were collected from different habitats (i.e., disturbed areas and mature forests), and their EMF communities were investigated by morphotype sequencing and next-generation sequencing (NGS). To infer assembly mechanisms, phylogenetic relatedness within the community (i.e., phylogenetic structure) was estimated and spatial distribution of EMF root tips was analyzed. The EMF communities on pine seedlings were largely different between the two habitats. Phylogenetically restricted lineages (Amphinema, /suillus-rhizopogon) were abundant in the disturbed areas, whereas species from diverse lineages were abundant in the mature forests (Russula, Sebacina, /tomentella-thelephora, etc.). In the disturbed areas, phylogenetically similar EMF species were aggregated at the seedling scale, suggesting that disturbance acts as a powerful abiotic filter. However, phylogenetically similar species were spatially segregated from each other at the root tip scale, indicating limiting similarity. In the mature forest seedlings, no distinct phylogenetic signals were detected at both seedling and root tip scale. Collectively, our results suggest that limiting similarity may be an important assembly mechanism at the root tip scale and that assembly mechanisms can vary across habitats and spatial scales.
外生菌根真菌（ectomycorrhizal fungi，EMF）与宿主植物的根系形成共生关系。EMF 群落由高度多样化的物种组成；然而，它们是如何组装的一直是一个悬而未决的问题。在这项研究中，我们从系统发育的角度研究了 EMF 群落如何在不同空间尺度（即幼苗尺度和根尖尺度）上组装在赤松幼苗上。从不同生境（即干扰区和成熟林）收集赤松幼苗，并通过形态型测序和下一代测序（NGS）研究其 EMF 群落。为了推断组装机制，我们估计了群落内的系统发育相关性（即系统发育结构），并分析了 EMF 根尖的空间分布。两种生境中，松树苗上的 EMF 群落差异很大。在干扰区，受限制的谱系（如 Amphinema、/suillus-rhizopogon）丰富，而在成熟林中，来自不同谱系的物种丰富（如 Russula、Sebacina、/tomentella-thelephora 等）。在干扰区，系统发育相似的 EMF 物种在幼苗尺度上聚集在一起，表明干扰是一种强大的非生物过滤器。然而，在根尖尺度上，系统发育相似的物种彼此之间存在空间分离，表明存在限制相似性。在成熟林幼苗中，在幼苗和根尖尺度上均未检测到明显的系统发育信号。总的来说，我们的结果表明，限制相似性可能是根尖尺度上的一个重要组装机制，并且组装机制可以在不同的生境和空间尺度上发生变化。
