16S Manila clam
Total RNA was extracted using RNeasy Mini Kit (Qiagen, Hilden, Germany). RNA concentration and quality were assessed by Agilent 2100 Bioanalyzer (Agilent Techologies, Santa Clara, CA, USA.  The cDNA libraries were constructed using a Sure Select Strand-Specific mRNA Library (Agilent Technologies, Santa Clara, CA,USA) according to the manufacturer's protocols. Total RNA were retrotranscripted using SuperScript IV (ThermoFisher). The 16S libraries were constructed starting from cDNAs using a scpecifc primer pairs for the V3-V4 region of 16S gene. During amplification step, a single barcode for each sample was included. After a purification step the libraries were quantified with a Qubit Fluorometer (Invitrogen, Carlsbad, CA, USA) and pooled together according to their relative concentrations. Its concentration and quality was assesses by Agilent 2100 Bioanalyzer.  The library pool was sequenced on MiSeq 300 (Illumina, Davis, CA, USA) with 2x300 bp setup using Version2 chemistry