Sample_D
For each sample, metagenomic libraries were constructed using NEBNext Ultra DNA Library Prep Kit for Illumina (New England Biolabs, UK). The library quality and quantity were evaluated by gel electrophoresis, Qubit 2.0 Fluorometer (Life Technologies) and Agilent 2100 Bioanalyzer (Agilent Technologies). Sequencing was performed on Illumina Hiseq 2500 platform (Illumina, San Diego, CA, USA) in paired-end mode.