16SrRNA V3-V4 B2
The purified DNA fragments was collected for illumina miseq sequencing by IlluminaMiSeq sequencer (Illumina, SanDiego, CA, USA). Unique sequences with similarity 97% or more than that were clustered into one operational taxonomic units (OTUs) and the data were analyzed on the free online platform of Majorbio I-Sanger Cloud Platform (www.i-sanger.com)