16S sequence of digestive gland
Purified DNA samples were quantified using a Qubit 2.0 Fluorometer (Invitrogen; USA). MiSeq (Illumina, USA) libraries were prepared as per manufacturers protocol (16S Metagenomic Sequencing Library Preparation; Part # 15044223; Rev. B [Illumina; San Diego, CA, USA]). PCR was conducted with primer sets targeting the V3-V4 regions of the bacterial 16S rRNA gene: PCR1 forward (5 CCTACGGGNGGCWGCAG 3) and PCR1 reverse (5 GACTACHVGGGTATCTAATCC 3) and the internal transcribed spacer region (ITS) between the fungal 18S and 5.8S rRNA genes: ITS1 forward (5'-CTTGGTCATTTAGAGGAAGTAA-3') and ITS2 reverse (5' GCTGCGTTCTTCATCGATGC 3').