Fig. 3: Gene expression and flavonoid accumulation were related to rhizosphere microbial composition and poplar growth performance.

A Apigenin and tricin (including derivatives) heat map in the root systems of different poplar sections. 27 samples correspond to different colors (each color corresponds to one section). Asterisks denote the flavones that were enriched in Leuce (One-way ANOVA, P values < 0.05; P values are shown in the Source Data file). B Chemical structure formulas for apigenin and tricin. C Correlation network of flavonoid-related genes, flavones, and ASVs in Cluster IV. Red color indicates genes detected in the network. Highly correlated associations (two-sided; Pearson; r ≥ 0.7, P values < 0.01) were present. D Correlation network of the top 20 microbial families with flavone modules and gene modules of Cluster IV (two-sided; Mantel test; P values < 0.05). The gene modules (00910 nitrogen metabolism, 00710 Carbon fixation by Calvin cycle, 00400 Phenylalanine, tyrosine, and tryptophan biosynthesis, 00360 phenylalanine metabolism, 00940 phenylpropanoid biosynthesis, and 00941 flavonoid biosynthesis) are modules of KEGG enrichment analysis in Cluster IV. The flavone modules are apigenin (with derivatives) and tricin (with derivatives) of Cluster IV. The node size represents the number of elements included (for example, the flavonoid biosynthesis module has 21 genes). Solid edges indicate positive relationships. Edge thickness denotes the strength of correlations. E Pearson’s correlation between Pseudomonadaceae and the shoot and root biomass of poplars (two-sided). The gray shading around the line represents a confidence interval of 0.95. F Pearson’s correlation (two-sided) between dominant genera and eleven characteristics of poplars. The color of the heat map represents the size of the correlation coefficient. Source data are provided as a Source Data file.