Soil+NaNO3+PE MPs on day 45
16S rRNA gene was amplified using 341F and 805R primers, targeting V3-V4 variable regions and 2X sparQ HiFi PCR master Mix (QuantaBio, USA). The amplification condition included an initial denaturation step 2 min at 98 C, followed by 30 cycles of 98C for 20 s, 60C for 30 s, and 72C for 30 sec, followed by a single step final extension step at 72C for 1 min. Subsequently, 16S amplicons were purified using sparQ Puremag Beads (QuantaBio, USA) and indexed using 5 l of each Nextera XT index primer in a 50 l PCR reaction, followed by 10 cycles of PCR condition above. The final PCR products were cleaned, pooled and diluted to final loading concentration at 4 pM. MiSeq500 cycles (V2) reagent kit and cluster generation and 250-bp paired-end read sequencing were performed on an Illumina MiSeq at Omics Sciences and Bioinformatics Center (Chulalongkorn University, Bangkok, Thailand).