sequences of bacteria
The bacterial 16S rRNA gene V3-V4 region was amplified using the forward primer 338F (5'-ACTCCTACGGGAGGCAGCA-3') and the reverse primer 806R (5'-GGACTACHVGGGTWTCTAAT-3'). Sequencing was performed using the Illumina NovaSeq platform (Illumina, San Diego, CA, USA) with dual-end 2356 bp reads.