Effects of host phylogeny, habitat and spatial proximity on host specificity and diversity of pathogenic and mycorrhizal fungi in a subtropical forest

Abstract

Summary Soil plant‐pathogenic (PF) and mycorrhizal fungi (MF) are both important in maintaining plant diversity, for example via host‐specialized effects. However, empirical knowledge on the degree of host specificity and possible factors affecting the fungal assemblages is lacking. We identified PF and MF in fine roots of 519 individuals across 45 subtropical tree species in southern China in order to quantify the importance of host phylogeny (including via its effects on functional traits), habitat and space in determining fungal communities. We also compared host specificity in PF and MF at different host‐phylogenetic scales. In both PF and MF, host phylogeny independently accounted for > 19% of the variation in fungal richness and composition, whereas environmental and spatial factors each explained no more than 4% of the variation. Over 77% of the variation explained by phylogeny was attributable to covariation in plant functional traits. Host specificity was phylogenetically scale‐dependent, being stronger in PF than in MF at low host‐phylogenetic scales (e.g. within genus) but similar at larger scales. Our study suggests that host‐phylogenetic effects dominate the assembly of both PF and MF communities, resulting from phylogenetically clustered plant traits. The scale‐dependent host specificity implies that PF were specialized at lower‐level and MF at higher‐level host taxa.

Community Assembly of Endophytic Fungi in Ectomycorrhizae of Betulaceae Plants at a Regional Scale

“…Furthermore, the endophytic fungal OTU richness was affected by host phylogeny, geographic distance, MAT and soil total N. Similar results were reported in previous studies on rootassociated fungal communities, such as EM fungi (Tedersoo et al, 2013;Wu et al, 2018;Wang et al, 2019a), AM fungi (Davison et al, 2015;Van Geel et al, 2018) and pathogenic fungi (Wang et al, 2019b). We found that host phylogeny significantly shaped endophytic fungal community composition.…”

“…In addition to environmental filtering by host plants, abiotic environmental variables including soil (pH, nutrients, and particle size distribution) and climate (MAT and MAP) have also been observed to affect endophytic fungal community in this study. Similar findings were also reported in some studies on root-associated fungal communities, such as endophytic fungi (Maciá-Vicente et al, 2012;Glynou et al, 2016), EM fungi (Jarvis et al, 2013;Miyamoto et al, 2015;Wang et al, 2019a), AM fungi (Dumbrell et al, 2010;Zheng et al, 2014;Van Geel et al, 2018), pathogenic fungi (Wang et al, 2019b), and total fungi (Barnes et al, 2018;Li et al, 2018). Fungal taxa are known to prefer to FIGURE 5 | Result of variation partitioning analysis showing pure and shared effects of plant, soil, climatic and spatial variables on endophytic fungal community composition.…”

“…The endophytic fungal community composition was also affected by geographic distance, which is in accordance with the community assembly of other root-associated fungi, such as EM fungi (Tedersoo et al, 2011;Matsuoka et al, 2016;Wang et al, 2019a), AM fungi (Dumbrell et al, 2010;Wang et al, 2019b), pathogenetic fungi (Schroeder et al, 2019;Wang et al, 2019b), and total fungi (Wehner et al, 2014;Beck et al, 2015;Schroeder et al, 2019). All spatial vectors (PCNM1-10) were retained as predictors for endophytic fungal community composition in this study, reflecting fungal community assembly at various spatial variation ranging from relatively small to large scales (Tedersoo et al, 2011;Wu et al, 2018;Wang et al, 2019a).…”

“…This finding coincides with previous studies concerning root-associated fungi involved in a wide phylogenetic spectra of plants (17 to 51 species of two to 39 genera belonging to one to 22 families) (Tedersoo et al, 2013;Wehner et al, 2014;Wu et al, 2018;Schroeder et al, 2019;Wang et al, 2019a,b), yet conflicts with studies only considered a set of closely related plant species (fewer than seven species in one genus) (Tedersoo et al, 2009;Glassman et al, 2015Glassman et al, , 2017Erlandson et al, 2016). For example, host phylogeny explained more variation of fungal community than spatial and soil variables in studies involving in 25 species of 22 genera in Asteraceae (Wehner et al, 2014) and 45 plant species in 39 genera from 22 families (Wang et al, 2019b). By contrast, in FIGURE 7 | Community-level interaction specialization and checkerboard score of endophytic fungal community.…”

“…For example, plant identity significantly shaped rootassociated ectomycorrhizal (EM) fungal communities (Ishida et al, 2007;Tedersoo et al, 2012;van der Linde et al, 2018) and arbuscular mycorrhizal (AM) fungal communities (Martinez-Garcia et al, 2015;Ciccolini et al, 2016;Zheng et al, 2016;Sepp et al, 2019) through host specificity, generating diverse substrates and changing microhabitats (Wardle, 2006;Dickie, 2007;Aponte et al, 2010). Likewise, an increasing amount of studies have indicated that host phylogeny strongly predicts root-associated fungal communities, such as total (Wehner et al, 2014;Schroeder et al, 2019), EM (Põlme et al, 2013;Tedersoo et al, 2013;Wu et al, 2018;Wang et al, 2019a), AM (Wang et al, 2019b), pathogenic (Schroeder et al, 2019;Wang et al, 2019b), and saprotrophic (Schroeder et al, 2019) fungi. According to phylogenetic niche conservatism, closely related plants are more similar in morphological and functional traits than distantly related ones (Losos, 2008), and maybe tend to associate with more similar fungal partners.…”