Biogeographic Patterns of Ectomycorrhizal Fungal Communities Associated With Castanopsis sieboldii Across the Japanese Archipelago.

Takashi Osono,Eri Kawaguchi,Hideyuki Doi,Shunsuke Matsuoka,Yoriko Sugiyama,Takaya Iwasaki

doi:10.3389/fmicb.2019.02656

Abstract

Biogeographic patterns in ectomycorrhizal (ECM) fungal communities and their drivers have been elucidated, including effects of host tree species and abiotic (climatic and edaphic) conditions. At these geographic scales, genotypic diversity and composition of single host tree species change with spatial and environmental gradients, reflecting their historical dispersal events. However, whether the host genotypes can be associated with the biogeographic patterns of ECM communities remains unclear. We investigated the biogeographic pattern of ECM fungal community associated with the single host species Castanopsis sieboldii (Fagaceae), whose genotypic diversity and composition across the Japanese archipelago has already been evaluated. ECM communities were investigated in 12 mature Castanopsis-dominated forests covering almost the entire distribution range of C. sieboldii, and we quantified the effect of host genotypes on the biogeographic pattern of ECM fungal communities. Richness and community composition of ECM fungi changed with latitude and longitude; these biogeographic changes of ECM community were significantly correlated with host genotypic variables. Quantitative analyses showed a higher relative explanatory power of climatic and spatial variables than that of host genotypic variables for the biogeographic patterns in the ECM community. Our results suggest historical events of host dispersal can affect the biogeographic patterns of the ECM fungal community, while their explanation power was lower than that for climatic filtering and/or fungal dispersal.

Highlights

Ectomycorrhizal (ECM) fungi are symbionts of tree species, for example Fagaceae, Betulaceae, Dipterocarpaceae, and Pinaceae, which can be found in a wide range of forest ecosystems throughout the world (Brundrett, 2009)
We aimed to evaluate the geographic pattern of ECM fungal community and the effect of host genotypes and genotypic diversity on that pattern by focusing on a single host species Castanopsis sieboldii (Makino) Hatus. ex T.Yamaz. et Mashiba (Fagaceae)
We considered C. sieboldii in Japan as the appropriate host species to evaluate the effect of host genotypes and genotypic diversity on the geographic distribution of the associated ECM fungal community

Summary

Introduction

Ectomycorrhizal (ECM) fungi are symbionts of tree species, for example Fagaceae, Betulaceae, Dipterocarpaceae, and Pinaceae, which can be found in a wide range of forest ecosystems throughout the world (Brundrett, 2009). Biogeography of Ectomycorrhizal Fungi the community responses to environmental changes, the relationships between spatial patterns of ECM fungal communities and factors responsible for those patterns have been investigated in previous studies (Lilleskov and Parrent, 2007). In these studies the spatial variations of ECM fungal community were related to key environmental factors including both biotic, such as species identity and phylogeny of the host (Ishida et al, 2007; Tedersoo et al, 2013), and abiotic factors, such as soil property (like soil pH) and climatic conditions (e.g., Bahram et al, 2012; Horton et al, 2013). The effects of these factors have been investigated at relatively small spatial scales, from forest to landscape scales (e.g., Tedersoo et al, 2011; Bahram et al, 2012; Matsuoka et al, 2016b)

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