*2.3. PCR Amplification*

PCR was performed to amplify the V1 to V3 region of the 16S rRNA gene from the samples' gDNA. 9F (5 -AGAGTTTGATCMTGGCTCAG-3 ) and 541R (5 -ATTACCGCGGCTGCTGG-3 ) primers were used in the amplification. The amplifications were carried out under the following conditions: initial denaturation at 94 ◦C for 5 min, followed by 30 cycles of denaturation at 94 ◦C for 30 s, primer annealing

at 55 ◦C for 30 s and extension at 72 ◦C for 30 s with a final extension phase at 72 ◦C for 5 min. The PCR products were visualized under a Gel Doc system (BioRad, Hercules, CA, USA) after electrophoresis on a 2% agarose gel. The amplified products were cleaned with the QIAquick PCR purification kit (Qiagen, Valencia, CA, USA).
