16S rRNA amplicon sequencing of the soil samples: soil VM with CM treatmnet replicate 2
DNA was subsequently amplified by polymerase chain reaction (PCR) targeting the V4 region of 16S rRNA (amplicon size ~250 bp; forward primer 515F: 5-GTGCCAGCMGCCGCGGTAA-3 and reverse primer 806R: 5-GGACTACHVGGGTWTCTAAT-3). To perform PCR, 10 L AmpliTaq Gold 360 Master Mix (Applied Biosystems, Foster City, CA, USA), 0.4 L of the forward primer, 0.4 L of the reverse primer, 7.2 L nuclease-free water and 1 L DNA extract were mixed. The first PCR cycle was set to 95C for 10 min and then 20 cycles at 95C for 30 s, 57C for 30 s and 72C for 1 min, followed by 72C for 7 min. The PCR products were subsequently purified with Agencourt AMPure XP (Beckman Coulter) according to the given protocol. Then, the purified products were quantified with the QuantiFluor ONE dsDNA System by a Quantus Fluorometer E6175 (Promega, Madison, WI, USA).