Plant-root pathogenic fungal and plant-mycorrhizal fungal association networks in a subtropical forest

Although rhizosphere fungi are essential for plant survival and ecosystem
functioning, little is known about the processes that structure
plant–fungal association networks. In this study, we constructed
association networks between 43 plant species and two groups of
root-associated fungi (mycorrhizal and pathogenic fungi; MF and PF,
respectively) in a diverse subtropical forest. We then evaluated the
modularity of plant–MF and plant–PF networks and linked them to the
functional traits and phylogenies of both plants and fungi. We observed
strong modularity in both plant–MF and plant–PF networks. Phylogenetically
related fungi tended to emerge in the same modules. MF from distinct
modules associated with plants with different specific root length and
specific root area in plant–MF networks. PF from distinct modules
associated with plants with different dark respiration rate and light
compensation point in plant–PF networks. Plant affiliation to modules was
explained by both plant traits and phylogeny (22% for plant–MF and 37% for
plant–PF networks). In contrast, fungal affiliation to modules was
explained by fungal phylogeny (16% for plant–MF and 29% for plant–PF
networks). Our results elucidate the link between modularity in plant–root
fungal networks and the functional traits and phylogeny of the plants and
fungi. Our study highlights the importance of traits and phylogeny in
governing root fungal community assembly from network perspective.