Effect of plant-soil feedback on soil microbial co-occurrence network depends on the stage of secondary succession

Co-occurrence networks of soil microbial community are used to describe co-occurrence relationships in microbial communities, which can better understand the structure, function, and interaction patterns of microbial communities at different succession stages, but how co-occurrence networks within microbial communities respond to the effects exerted by plants come from different successional stages is unknown. Changes in the cooccurrence network of soil fungal and bacterial communities after plant species grown under monoculture were analyzed with a greenhouse experiment using the rhizosphere soils collected from early-, mid-, and latesuccessional species in the field. Results showed that compared with the soil microbial communities of plants grew in their own soil conditions, significant changes were observed in the Chao1 and ACE richness of the fungal community and Shannon and Simpson indices of the bacterial community after the growth of plants in other stages of succession; the relative abundance of the bacterial communities were mainly affected rather than the fungal communities at the phylum level. The late-successional species (or mid-successional species) mainly increased the graph density and average clustering coefficient (network complexity) of the fungal and bacterial communities in soil conditioned by the early- and mid-successional species (or early-successional species). Soil water-soluble nitrogen and phosphorus were the main soil factor affecting the relative abundance of the fungal and bacterial communities in species succession. The pre-successional species may be replaced directly by the subsequent plant species in a succession sequence given the network complexity of soil microbial communities.