soil
Microbial diversity analysis was performed using the following procedures: DNA extraction was conducted with the E.Z.N.A. Soil DNA Kit (Omega Bio-tek, USA), followed by PCR amplification using FastPfu Polymerase (TransGen Biotech, China) on a T100 Thermal Cycler (Bio-Rad, USA). Electrophoresis was performed using a JY600C system (Junyi-Dongfang Electrophoresis Equipment, China). High-throughput sequencing was carried out on the Illumina Nextseq2000 platform (Majorbio Bio-Pharm Technology, Shanghai).Soil samples were stored at -80C immediately after collection. The quality of extracted genomic DNA was verified by 1% agarose gel electrophoresis, with concentration and purity measured using a NanoDrop2000 spectrophotometer (Thermo Scientific, USA).Using the extracted DNA as template, the V3-V4 hypervariable regions of bacterial 16S rRNA genes were amplified with the following thermal cycling protocol: initial denaturation at 95C for 3 min; 27 cycles of 95C for 30 s, 55C for 30 s, and 72C for 30 s; final extension at 72C for 10 min; and hold at 4C (PCR system: ABI GeneAmp 9700). PCR products were purified using 2% agarose gel electrophoresis and extracted with a DNA Gel Extraction Kit (PCR Clean-Up Kit, YuHua, China). Purified amplicons were sequenced on the Illumina Hiseq 2000 platform