2.4 Bioinformatics analysis
The bioinformatics analysis procedure is presented in Supplemental Information Methods. All the samples produced an average 79,168 bacterial tags and 103,364 fungal tags through reads splicing. After quality control, 76,509 bacterial effective reads and 85,563 fungal effective reads were obtained across all samples. The numbers of bacterial and fungal effective reads following the quality control were 49,093 and 64,266, respectively, while the quality control effective rates were 62% and 62%, respectively. Sequences were clustered into operational taxonomic units (OTUs) with a 97% similarity cut-off. A total of 13,034 bacterial OTUs and 8,705 fungal OTUs were obtained. The OTUs were then annotated with the Silva132 (bacterial) database and UNITE (fungi) database.