Freshwater Metagenome

The diversity of viruses in the Yangtze River remains largely unexplored. To investigate the freshwater virome from the Yangtze River, totally thirty litres of water samples were collected from six river ports along the Yangtze River in 2017. Each sample was condensed into one milliliter and vigorously vortexed for 5 min. The supernatants were then collected after centrifugation. 500 ul of each supernatant was filtered through a 0.45 um filter to remove eukaryotic and bacterial cell sized particles. The filtrates enriched in viral particles were treated with DNase and RNase to digest unprotected nucleic acid for 60 min. Remaining total nucleic acid was then isolated using QIAamp MinElute Virus Spin Kit according to manufacturer protocol. Six libraries were then constructed using Nextera XT DNA Sample Preparation Kit and sequenced using the Illumina MiSeq platform with 250 bases paired ends with dual barcoding for each library. For bioinformatics analysis, paired end reads of 250 bp generated by Illumina MiSeq platform were debarcoded using vendor software from Illumina.