Processing and analyses of 16S rRNA gene amplicons
The amplicons, originating from two different library designs, were
processed as two independent data sets. The raw data were quality
checked in FastQC (Andrews, 2010) and trimmed using USEARCH v9.0.1001
(Edgar, 2013). The reads were further processed and clustered into OTUs
(operational taxonomic units) according to the workflow implementing
USEARCH v9.0.1001 scripts. All putative contaminants found in negative
controls were discarded and highly abundant, potentially symbiotic, OTUs
were identified. Details on the read processing, decontamination and OTU
filtering, including the accession links to the raw data, are provided
in the SupplementaryInformation/SupplementaryText.