Analysis of virus genomes from glacial environments reveals novel virus groups with unusual host interactions.

摘要: Microbial communities in glacial ecosystems are diverse, active, and subjected to strong viral pressures infection rates. In this study we analyse putative virus genomes assembled from three dsDNA viromes cryoconite hole of Svalbard the Greenland Ice Sheet assess potential hosts functional role viruses play these habitats. We 208 million reads virus-size fraction developed a procedure select genuine scaffolds cellular contamination. Our curated library contained 546 up 230 Kb length, 54 which were circular consensus genomes. Analysis marker genes revealed wide range had been assembled, including bacteriophages, cyanophages, nucleocytoplasmic large DNA virophage, with identified as Cyanobacteria, Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, Firmicutes, eukaryotic algae amoebae. Whole genome comparisons majority (CGS) formed 12 novel groups, two multiple phage members plasmid-like properties, group phage-plasmids possessing partition toxin-antitoxin addiction modules ensure their replication satellite phage-plasmid group. Surprisingly also that not only encoded plasmid genes, but clustered regularly interspaced short palindromic repeat (CRISPR)/Cas adaptive bacterial immune system. One spacers was an exact match for another our virome, indicating use system, lysogen potentially capable conferring immunity on its host against other phage. Together results suggest highly diverse groups present environments, some utilize very unusual life strategies control maintain long-term relationship hosts.