title: 16S amplicon extraction control
design: The full-length of the 16S  rRNA genes were sequenced on a Pacbio Sequel II (PacBio Biosciences Inc., CA, USA). Preparation and sequencing of full-length (V1-V9) 16S rRNA gene libraries were done by the sequencing core center of University of Georgia (Athens, GA, USA) as described previously (Schloss et al., 2015).