16S amplicon sequencing
DNA was PCR amplified by using the primer pair 515F-Y (5-GTGYCAGCMGCCGCGGTAA-3) and 926R (5- CGYCAATTYMTTTRAGTTT-3), which encompass the V4 and V5 hypervariable loops of 16S rRNA genes (Parada et al. 2015).. Libraries were prepared following the 16S Metagenomic Sequencing Library Preparation protocol and run on an Illumina MiSeq System for a read length of 2  250 bp.