16S METAGENOMICS
Single-end reads was assigned to samples  based on their unique barcode and truncated by cutting off the barcode and  primer sequence. Quality filtering on the raw reads were performed under  specific filtering conditions to obtain the high-quality clean reads[15]  according to the Qiime(V1.7.0,  http://qiime.org/scripts/split_libraries_fastq.html)[16]quality controlled  process. The reads were compared with the reference database(Gold  database,http://drive5.com/uchime/uchime_download.html) using UCHIME algorithm  (UCHIME Algorithm,http://www.drive5.com/usearch/manual/uchime_algo.html)[17]  to detect chimera sequences  (http://www.drive5.com/usearch/manual/chimera_formation.html). And then the  chimera sequences were removed [18]. Then the Effective Reads finally  obtained.