Viruses of microorganisms in the Baltic Sea: current state of research and perspectives

ABSTRACT

This paper reviews the current state of research into viruses of microorganisms in the Baltic Sea. Field and experimental studies reveal the great phenotypic and genotypic variety of the Baltic Sea viruses and highlights the importance of phages in the Baltic Sea food-web dynamics. In total, 93 virus isolates from the Baltic Sea have been described, the genome sequence being available for 39 of these. However, these isolates were derived from only eight host species and, therefore, underrepresent the overall viral diversity in the Baltic Sea. The most studied group of viruses is bacteriophages that infect Bacteroidetes, whereas, by contrast, phages of Cyanobacteria, Proteobacteria and Actinobacteria, as well as algal viruses, have been investigated to a lesser extent. No reports on viruses infecting Baltic Sea fungi and archaea isolates have been reported to date. This paper also identifies gaps in our knowledge of the aquatic virology of the Baltic Sea and emphasizes the need for more comprehensive analysis of those viruses that occur in one of the world's largest brackish water ecosystems.

RESPONSIBLE EDITOR:

• Mathias Middleboe

KEYWORDS:

• Bacteriophages
• brackish water ecosystem
• cyanophages
• culture isolates
• lytic infections
• virus diversity

Acknowledgements

We thank Mathias Middelboe, a Subject Editor, and two anonymous reviewers, whose advice and suggestions considerably improved the final version of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Sigitas Šulčius http://orcid.org/0000-0002-2686-8348

Additional information

Funding

This research was funded by a grant (No. MIP-036/2012) from the Research Council of Lithuania to SŠ and from the Swedish Research Council (2013-4554) to KH.