Investigating the Diversity of Marine Bacteriophage in Contrasting Water Masses Associated with the East Australian Current (EAC) System

Abstract

Virus- and bacteriophage-induced mortality can have a significant impact on marine productivity and alter the flux of nutrients in marine microbial food-webs. Viral mediated horizontal gene transfer can also influence host fitness and community composition. However, there are very few studies of marine viral diversity in the Southern Hemisphere, which hampers our ability to fully understand the complex interplay of biotic and abiotic factors that shape microbial communities. We carried out the first genetic study of bacteriophage communities within a dynamic western boundary current (WBC) system, the east Australian current (EAC). Virus DNA sequences were extracted from 63 assembled metagenomes and six metaviromes obtained from various depths at 24 different locations. More than 1700 bacteriophage genomic fragments (>9 kbps) were recovered from the assembled sequences. Bacteriophage diversity displayed distinct depth and regional patterns. There were clear differences in the bacteriophage populations associated with the EAC and Tasman Sea euphotic zones, at both the taxonomic and functional level. In contrast, bathypelagic phages were similar across the two oceanic regions. These data provide the first characterisation of viral diversity across a dynamic western boundary current, which is an emerging model for studying the response of microbial communities to climate change.

Isolation and Characterisation of the Bundooravirus Genus and Phylogenetic Investigation of the Salasmaviridae Bacteriophages

“…We also noticed a correlation of cluster formation with the geographical location of phage isolation. This pattern is likely driven by the host bacterium’s biogeography and population; this may become clearer as more Salasmaviridae phages are isolated and sequenced [ 72 , 73 ].…”

Microbial tropicalization driven by a strengthening western ocean boundary current

“…While the impact of shifting WBC flow regimes on the macroecology of marine systems is beginning to become apparent, to date there is little understanding of how climate change-driven shifts in WBCs will influence the dynamics of the planktonic microbes that drive ocean productivity and global biogeochemical cycles. Investigations into bacterioplankton community structure and functional potential within WBCs are relatively limited (Focardi, Ostrowski, Goossen, Brown, & Paulsen, 2020;Phoma et al, 2018;Seymour et al, 2012), with the majority of research in this area focussed on characterizing nitrogen fixing prokaryotes in the Kuroshio Current (Cheung et al, 2017;Shiozaki et al, 2010Shiozaki et al, , 2014Shiozaki et al, , 2015Shiozaki et al, , 2018. Although there is some evidence that physical advection of planktonic microbes can shape the process of community assembly (Barton et al, 2010;Cheung, Suzuki, Xia, & Liu, 2018;Galand et al, 2009;Shiozaki et al, 2015), the dynamics of microbial assemblages carried by surface currents through shifting environmental conditions are poorly defined outside of model simulations (Doblin & van Sebille, 2016).…”

Phylogenomic analysis expands the known repertoire of single-stranded DNA viruses in benthic zones of the South Indian Ocean

“…Several of these AMGs related to amino acid metabolism included 2OG-Fe(II) oxygenases (arginine and proline metabolism). Previous studies suggest that these AMGs may modulate host nitrogen metabolism, stress response, and DNA repair mechanisms [ 100–102 ]. Some of the genes linked to these AMGs are involved in the metabolism of cysteine and methionine, linked to carbon, nitrogen, and sulphur utilization, and the reprogramming of cells to anabolic states [ 103 ].…”