DNA extraction and Illumina MiSeq sequencing

The EZNATM Soil DNA Kit (Omega, United States) was used to extract the DNA of the soil at a UV-sterilized ultraclean bench. We used 1% (m/v) agarose gel electrophoresis to analyze the eluted DNA samples and used a NanoDrop® ND-1000 UV–Vis spectrophotometer (Thermo Fisher Scientific, United States) to measure the DNA concentration. The V3-V4 hypervariable regions of the bacterial 16S rRNA gene were amplified using Liu et al. (2021) method with the primer (338F 5′- ACTCCTACGGGAGGCAGCAG-3′ and 806R 5′-GGACTACHVGGGTWTCTAAT-3′). Amplification was performed with predenaturation for 3 min at 95°C, followed by 26 cycles of 30 s at 95°C, 30 s at 55°C, and 45 s at 72°C, and final extension for 10 min at 72°C. PCR amplicons were detected by electrophoresis on 2% (w/v) gels, and the Axygen® AxyPrep DNA Gel Extraction Kit (Axygen Biosciences, United States) was used to recover the target fragments. The purified amplicons were sequenced on the Illumina MiSeq PE250 sequencer.