Fine-scale distribution of ectomycorrhizal fungi colonizing Tsuga diversifolia seedlings growing on rocks in a subalpine Abies veitchii forest

Abstract

Numerous species of ectomycorrhizal (ECM) fungi coexist under the forest floor. To explore the mechanisms of coexistence, we investigated the fine-scale distribution of ECM fungal species colonizing root tips in the root system of Tsuga diversifolia seedlings in a subalpine forest. ECM root tips of three seedlings growing on the flat top surface of rocks were sampled after recording their positions in the root system. After the root tips were grouped by terminal-restriction fragment length polymorphism (T-RFLP) analysis of ITS rDNA, the fungal species representing each T-RFLP group were identified using DNA sequencing. Based on the fungal species identification, the distribution of root tips colonized by each ECM fungus was mapped. Significant clustering of root tips was estimated for each fungal species by comparing actual and randomly simulated distributions. In total, the three seedlings were colonized by 40 ECM fungal species. The composition of colonizing fungal species was quite different among the seedlings. Twelve of the 15 major ECM fungal species clustered significantly within a few centimeters. Some clusters overlapped or intermingled, while others were unique. Areas with high fungal species diversity were also identified in the root system. In this report, the mechanisms underlying generation of these ECM root tip clusters in the root system are discussed.

Temperature niche position and breadth of ectomycorrhizal fungi: Reduced diversity under warming predicted by a nested community structure

“…Fungal community composition was examined using the sites where a uniform sampling method with equal soil core volume (250 cm 3 per core) was applied (“community” data type in Table ). Four of the 26 sites were surveyed using different methods and were only used for distribution analyses: EM root collection from seedlings (Yoshida, Son, Matsushita, Iwamoto, & Hogetsu, ) and by root tracing (Ishida, Nara, & Hogetsu, ), and EM fungal survey associated with Tricholoma (Lian, Narimatsu, Nara, & Hogetsu, ) and orchids (Ki, Nara unpublished). Based on BLAST results, some OTUs that were defined at ≥97% sequence similarity existed outside our study regions.…”

Small‐scale spatial variability in the distribution of ectomycorrhizal fungi affects plant performance and fungal diversity

“…), and down to a few centimetres (Yoshida et al . ). Although generally overlooked, it is the small‐scale variability in mycorrhizal inoculum available to individual plants that has potentially large‐scale effects on plant performance.…”

“…EM fungal inoculum are not uniformly distributed in space, exhibiting heterogeneity at scales ranging from thousands of kilometres (Talbot et al 2014;Tedersoo et al 2014;Glassman et al 2015), through metres (Izzo et al 2006;Pickles et al 2010;Bahram et al 2012), and down to a few centimetres (Yoshida et al 2014). Although generally overlooked, it is the small-scale variability in mycorrhizal inoculum available to individual plants that has potentially large-scale effects on plant performance.…”

A single ectomycorrhizal plant root system includes a diverse and spatially structured fungal community

“…Even in seedlings and herbaceous plants, the number of species is surprisingly high. The number of root associated operational taxonomic units (OTUs, a proxy for species) may range from 37 to 159 within single root systems of the EcM forming plant B. vivipara (Yao et al 2013), and Yoshida et al (2014) found 40 species of EcM fungi associated with three Tsuga diversifolia seedlings.…”

“…They later confirmed that root systems were dominated by the earlier coloniser (Kennedy et al 2009), and that priority effects determined the outcome. Yoshida et al (2014) investigated the fine scale structure of three seedlings of T. diversifolia from a natural environment, and similarly observed that the priority effect was likely important in structuring the EcM fungal community, as clusters of root tips colonised by individual species were observed in the root system. However, in mature forest systems, competitive interactions seem to be the determining process in structuring EcM communities at finer scales (Pickles et al 2012).…”