High-Resolution Temporal and Spatial Patterns of Virome in Wastewater Treatment Systems

Wastewater
treatment plants (WWTPs) are considered reservoirs of viruses, but
the diversity and dynamic changes of viruses are not well understood.
In this study, we recovered 8478 metagenomic viral contigs (mVCs; >5
kb) from two WWTPs (Shatin, 2806; Shek Wu Hui, 5672) in Hong Kong.
Approximately 60% of the mVCs were poorly covered (<35% of genes
in identified mVCs) by the current NCBI and IMG/VR viral databases.
The temporal profile of the newly identified mVCs among 98 Shatin
AS samples collected monthly (for approximately 9 years) revealed
the presence of periodic dynamics at an interval of approximately
one year (341 days). The spatial distribution pattern of the virome
in the wastewater treatment systems showed that shared viral clusters
(viral populations categorized based on shared gene content and network
analysis) can be globally found among similar samples of wastewater
treatment systems, indicating the presence of core viral communities
among geographically isolated wastewater treatment systems. These
results not only supplemented the current virome database of engineered
systems but also, to some extent, expanded the understanding of long-term
cyclical development and spatial distributions of viral communities
in wastewater treatment systems.