Note: (a) Rhizosphere soil fungal topology parameters; (2)
nonrhizosphere soil fungal network topology parameters. Different
uppercase letters indicate the following: A, average degree; B, average
path length; C, clustering coefficient; D, network degree centrality; E,
network tight centrality; F, network efficiency; G, network quality; H,
information center; I, network vulnerability; J, network stability.
Fig. 5 Topological properties of the soil fungal community networks ofA. spinulosa at different taxonomic levels
Predictive analysis of fungal function
FUNGuild functional prediction analysis revealed that the soil fungi ofA. spinulosa included nine main groups: pathotroph, symbiotroph,
saprotroph, saprotroph–symbiotroph, pathotroph–symbiotroph,
pathotroph–saprotroph, saprotroph–pathotroph–symbiotroph,
pathotroph–saprotroph–symbiotroph, and
pathogen–saprotroph–symbiotroph. Soil fungi in both A.
spinulosa rhizosphere and nonrhizosphere were predominantly saprophytic
trophic (saprotroph), with the proportion of pathotrophs being higher in
the A. spinulosa rhizosphere (10.51% vs. 7.76%).
In total, 108 functional groups were detected through functional group
identification, and 15 of them had a relatively high abundance (Fig. 6).
The main functional groups of symbiotrophs and saprotrophs in the
rhizosphere and non-rhizosphere soils of A. spinulosa were
identical. The main functional groups of symbiotrophs were arbuscular
mycorrhizal, ectomycorrhizal, and endophyte fungi. Saprotrophs comprised
undefined saprotroph, soil saprotroph, and wood saprotroph as the main
functional groups. The main functional groups of pathotrophs betweenA. spinulosa rhizosphere and nonrhizosphere soils were identical:
animal pathogen, phytopathogen, and fungal parasite–lichen parasite.
However, the status of the functional groups differed, with the animal
pathogen predominating the A. spinulosa rhizosphere soil and the
phytopathogen predominating the nonrhizosphere soil. Compared with fungi
in the nonrhizosphere soil, the relative abundance of fungi in the
rhizosphere soil of A. spinulosa increased for animal pathogens
and saprotroph–symbiotroph and decreased for pathotroph–saprotroph.