FIGURE LEGENDS
FIGURE 1Effects of soil microorganisms on plant fitness (mean ± SE, n = 3). The following metrics were used for this comparison: (a) biomass accumulation, (b) allocation patterns, and (c) leaf dry mass per unit area (LMA) of N. tabacum grown in continuous cropping soil (CCS) and natural fallow soil (FS). Significance values of the factorial analysis (ANOVA) for the effects are indicated as follows: *,p < 0.05; **, p < 0.01. Filled (or open) points show soil without (or with) sterilization treatment.
FIGURE 2Overview of the taxonomy of bacterial diversity on phylum level in (a) bulk soil and (b) rhizosphere of CCS and FS.
FIGURE 3 Principal coordinate analysis (PCoA) using Bray-Curtis distance between samples for taxonomic profiles of bacteria and fungi (operational taxonomic unit (OUT) level for the 16S rRNA data set) for bulk soils and rhizosphere of CCS and FS. Permutational multivariate analysis of variance (PERMANOVA) was used to assess group differences.
FIGURE 4 Significantly retrieved discriminant taxa for bulk soil and rhizosphere bacterial and fungi communities of CCS and FS. The cladogram provides a taxonomic representation of statistically consistent differences between rhizosphere and bulk soil for (a) bacterial communities, (b) fungal communities, and (c) bacterial communities of the reassembled soil microbial communities. The tables below each cladogram report phyla/classes that statistically significantly discriminated bulk soilvs rhizosphere. Filter criteria: for bacterial microbiomes: LDA score > 4.0, p < 0.05; for fungal microbiomes: LDA score > 3.0, p < 0.05.