Continuous year-round isolation of giant viruses from brackish shoreline soils

• Published in: Frontiers in microbiology Vol. 15; p. 1402690
• Main Authors: Akashi, Motohiro, Takemura, Masaharu, Suzuki, Seiichi
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 02-05-2024
• Subjects: brackish water; giant virus; microbial ecology; Microbiology; NCLDV; soil; giant virus; soil; NCLDV; microbial ecology; brackish water
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2024.1402690

Giant viruses, categorized under
are believed to exist ubiquitously in natural environments. However, comprehensive reports on isolated giant viruses remain scarce, with limited information available on unrecoverable strains, viral proliferation sites, and natural hosts. Previously, the author highlighted
,
, and
sp. styx, isolated from brackish water soil, as potential hotspots for giant virus multiplication. This study presents findings from nearly a year of monthly sampling within the same brackish water region after isolating the three aforementioned strains. This report details the recurrent isolation of a wide range of giant viruses. Each month, four soil samples were randomly collected from an approximately 5 × 10 m plot, comprising three soil samples and one water sample containing sediment from the riverbed.
was used as a host for virus isolation. These efforts consistently yielded at least one viral species per month, culminating in a total of 55 giant virus isolates. The most frequently isolated species was
(24 isolates), followed by
(23 isolates),
(6 isolates), and singular isolates of
and
. Notably, viruses were not consistently isolated from any of the four samples every month, with certain sites yielding no viruses. Cluster analysis based on isolate numbers revealed that soil samples from May and water and sediment samples from January produced the highest number of viral strains. These findings underscore brackish coastal soil as a significant site for isolating numerous giant viruses, highlighting the non-uniform distribution along coastlines.