2.2. DNA extraction and Illumina sequencing of the 16S rRNA
gene
DNA was extracted following the manufacturer’s protocol using the
FastDNA SPIN kit (MP bio, CA, USA). The DNA was dissolved in 100 µL of
sterilized deionized water and stored at –18 °C until further analysis.
NanoDrop (ND-1000, USA) was used to detect DNA concentration and
OD260/OD280. For the Illumina sequencing, the archaeal 16S rRNA genes
were amplified using the primer pair 524F10extF/Arch958RmodR
(5’-TGYCAGCCGCCGCGGTAA-3’/5’-YCCGGCGTTGAVTCCAATT-3’) (Liu et al. 2016),
with 2 µL of DNA samples used as the template. Purified amplicons were
sequenced using Illumina MiSeq PE300 (Illumina, San Diego, USA) by
Majorbio Bio-Pharm Technology Co. Ltd. (Shanghai, China).