FIGURE 4.

Associations of rare species and samples in PRM study. (A) Communities of associated fungal and bacterial OTUs discovered by the Anets-OTUs algorithm in rhizoshpere of Populus deltoides. Nodes in the network indicate OTUs and edges indicate pair-wise association between them. The node color shows the community (cluster) assignment inferred by clustering. (B) Presence–absence map of the associated OTUs; the cell color is red if OTU is present in the sample and it is black if OTU is absent. OTUs are grouped according to the microbial communities inferred by Anets-OTUs and sorted by mean abundance; samples are grouped according to clusters inferred by Anets-Samples and sorted by the shared richness. (C) Two associations of Populus rhizoshpere samples with the shared species richness revealed by Anets-Samples; color indicates samples taken in NC (red) and in TN (green). (D) Hierarchical clustering of the soil properties; brackets indicate three cluster of soil samples with distinct soil properties: green bracket indicates the cluster of soil samples that correspond to the association of rhizosphere samples in TN, red bracket indicates the cluster of soil samples that correspond to the association of rhizosphere samples in NC, black bracket and black squares indicate samples that don’t found as associated by Anets-Samples.