Similar to prior published works, DNA was extracted using the ZymoBIOMICS DNA Microprep Kit (Zymo Research, Irvine, CA, USA) per the manufacturer’s protocol. The V4 region of the 16S ribosomal RNA gene was amplified by PCR and underwent 250 × 2 paired-end sequencing on an Illumina HiSeq (Illumina, San Diego, CA, USA) [27 (link),28 (link)]. The sequences were processed using the DADA2 pipeline in R which assigns taxonomy using the SILVA 132 database [29 (link)]. After pre-processing in R, the data were incorporated into QIIME 2 version 2019.10 [30 (link)]. Amplicon sequence variants were filtered if not present in at least 15% of all samples. Sequence depths ranged from 60,710 to 269,258 per sample.
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