Abstract
Viruses play vital biogeochemical and ecological roles by (a) expressing auxiliary metabolic genes during infection, (b) enhancing the lateral transfer of host genes, and (c) inducing host mortality. Even in harsh and extreme environments, viruses are major players in carbon and nutrient recycling from organic matter. However, there is much that we do not yet understand about viruses and the processes mediated by them in the extreme environments such as hypersaline habitats. The Great Salt Lake (GSL) in Utah, United States is a hypersaline ecosystem where the biogeochemical role of viruses is poorly understood. This study elucidates the diversity of viruses and describes virus–host interactions in GSL sediments along a salinity gradient. The GSL sediment virosphere consisted of Haloviruses (32.07 ± 19.33%) and members of families Siphoviridae (39.12 ± 19.8%), Myoviridae (13.7 ± 6.6%), and Podoviridae (5.43 ± 0.64%). Our results demonstrate that salinity alongside the concentration of organic carbon and inorganic nutrients (nitrogen and phosphorus) governs the viral, bacteria, and archaeal diversity in this habitat. Computational host predictions for the GSL viruses revealed a wide host range with a dominance of viruses that infect Proteobacteria, Actinobacteria, and Firmicutes. Identification of auxiliary metabolic genes for photosynthesis (psbA), carbon fixation (rbcL, cbbL), formaldehyde assimilation (SHMT), and nitric oxide reduction (NorQ) shed light on the roles played by GSL viruses in biogeochemical cycles of global relevance.
Highlights
Viruses are the most abundant biological entities (Bergh et al, 1989; Fuhrman, 1999; Suttle, 2005; Nooij et al, 2018; Graham et al, 2019) which infect all forms of known cellular life
Variability in dissolved oxygen (DO) in the deep layer of the overlying water column was observed with the oxygen-rich zone in GB14 (DO: 6.84 mg/L), oxygen deficiency in Great Salt Lake (GSL) 3510 (DO: 0.44 mg/L), and anoxia in CB2 (DO ∼ 0 mg/L) (Table 1)
Our study found ten metagenome assembled genome (MAG) including those classified as Desulfobacteraceae, Desulfohalobiaceae, Planctomycetaceae, encoding genes involved in the reductive acetyl-CoA, or Wood– Ljungdahl (WL) pathway in GSL sediments (Figure 5B)
Summary
Viruses are the most abundant biological entities (Bergh et al, 1989; Fuhrman, 1999; Suttle, 2005; Nooij et al, 2018; Graham et al, 2019) which infect all forms of known cellular life. Viruses encode AMGs, host derived genes that are expressed during infection to re-direct hosts metabolism toward pathways that promote viral productivity (Sullivan et al, 2006; Hurwitz and U’Ren, 2016). These genes, AMG, are involved in various metabolisms, including sulfur, nitrogen, and methane, in DNA replication, repair, recombination, and amino acid biosynthesis, and are detected in extreme environments (Anantharaman et al, 2014; Anderson et al, 2014; Ahlgren et al, 2019). Such AMGs exemplify how viruses can affect biogeochemical cycles of global relevance in ways which beyond killing of their hosts
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
