FTG_3 (CRX825787; CRA012926)
We diluted the DNA to 1 ng/microL solution with sterile water and amplified the 16S rRNA V3-V4 regions using 338F and 806R primers with Phusion High-Fidelity PCR Master Mix (New England Biolabs, Boston, MA, USA). We then purified the PCR products using the AxyPrep DNA Gel Extraction Kit (Axygen, New York, NY, USA). Next, we used the NEBNext Ultra DNA Library Prep Kit (New England Biolabs, Boston, MA, USA) to construct the libraries and committed the products to the MiSeq platform (Illumina, San Diego, CA, USA) for 225-nt paired-end sequencing after library quality assessment (Qubit 2.0 Fluorometer, Thermo Scientific, CA, USA).