FIGURE 2 Differential abundance of bacterial (A) and fungal (B)
OTUs in the rhizosphere soil of different samples (at the phylum level).
The Welch T-test was used for statistical analysis. The Bonferroni
method was used for multiple hypothesis test correction. ‘*’:
P<0.05, ‘***’: P<0.01.
3.5 | Core microbial community
As shown in Figure 3, 5,017 bacterial OTUs were detected in the three
families. Among them, 1,221 OTUs were found in all samples, accounting
for 24.34% of all OTUs. OTUs with an abundance of more than 1% were
selected as representative of the core bacterial family. These OTUs were
assigned to various genera. Within Acidobacteria,norank_Subgroup2 accounted for the largest proportion of the
genera (containing 12 OTUs, with a relative abundance of 75.32%),
followed by norank_Acidobacteriales (3 OTUs, relative abundance
14.00%). Acidibacter (4 OTUs, relative abundance 34.19%),norank_Xanthobacteraceae (2 OTUs, relative abundance 19.85%),Burkholderia-Caballeronia-Paraburkholderia (2 OTUs, relative
abundance 19.14%), and Bradyrhizobium (1 OTU,
relative abundance 8.91%) were the
most abundant in Proteobacteria, and HSB_OF53-F07 was the most
abundant in Chloroflexi (1 OTU, relative abundance 2.90%). In the box
plots corresponding to each bacterial genus, the abundances ofAcidothermus and Bryobacter in Acidobacteria showed a
trend of leveling off or decreasing first and then increasing,
respectively, with increasing carbon sequestration. However, the
relative abundance of each genus in Proteobacteria and Chloroflexi
decreased to different degrees with the increase in carbon sequestration
in the samples (Figure 3).
A total of 2,300 fungal OTUs were detected in the three families. Among
them, 254 OTUs were found in all samples, accounting for 11.04% of all
fungal OTUs. According to the bacterial classification method, these
OTUs belonged to unclassified_Basidiomycota (1 OTU, relative
abundance 33.74%), Russula (1 OTU, relative abundance 26.36%),Saitozyma (1 OTU, relative abundance 19.30%) andGeminibasidium (1 OTU, relative abundance 19.16%) in
Basidiomycota. Unclassified_Ascomycota (4 OTUs, relative
abundance 37.91%), Penicillium (1 OTU, relative abundance
32.25%), Archaeorhizomyces (2 OTUs, relative abundance 14.32%),Oidiodendron (1 OTU, relative abundance 6.70%), andunclassified_Helotiales (1 OTU, relative abundance 4.89%) were
the most abundant genera in Ascomycota, and Umbelopsis (1 out, relative
abundance 4.38%) was the most abundant in Mucoromycota. In the box
plots, in Basidiomycota, the relative abundance of all genera exceptSaitozyma showed an increasing trend with the increase in carbon
sequestration. However, the relative abundances of fungi in Ascomycota
and Mucoromycota showed a continuously decreasing trend except that the
relative content of Penicillium decreased first and then
increased (Figure S2).