Metagenome sequencing
Total microbial genomic DNA samples were extracted using the OMEGA Mag-Bind SoilDNA Kit (M5635-02) (Omega Bio-Tek, Norcross, GA, USA), following the manufacturersinstructions, and stored at -20C prior to further assessment. The quantity and quality ofextracted DNAs were measured using a Qubit 4 Fluorometer, with WiFi: Q33238 (Qubit Assay Tubes: Q32856; Qubit 1X dsDNA HS Assay Kit: Q33231) (Invitrogen, USA) andagarose gel electrophoresis, respectively. The extracted microbial DNA was processed toconstruct metagenome shotgun sequencing libraries with insert sizes of 400 bp by usingIllumina TruSeq Nano DNA LT Library Preparation Kit. Each library was sequenced byIllumina NovaSeq platform (Illumina, USA) with PE150 strategy at Personal BiotechnologyCo., Ltd. (Shanghai, China)