Smaller fleas: viruses of microorganisms

Area of Science:

• Microbiology
• Virology
• Genetics

Background:

• Cellular life can be broadly classified as microscopic or macroscopic, and unicellular or multicellular.
• Microscopic and less-than-truly-multicellular organisms commonly host viruses.
• Viruses of microorganisms (VoMs) represent the most abundant autonomous genetic entities globally.

Purpose of the Study:

• To introduce the concept of viruses of microorganisms (VoMs).
• To discuss the diversity of VoMs across different microbial domains.
• To provide an overview of the current understanding of VoM families and their hosts.

Main Methods:

• Review and synthesis of existing literature on microbial viruses.
• Categorization of VoMs based on their host domains (Bacteria, Archaea, Fungi, Protists).
• Estimation of the number of virus families infecting microorganisms.

Main Results:

• VoMs encompass viruses infecting bacteria (bacteriophages), archaea (archaeal viruses), protists, and microscopic fungi (mycoviruses).
• Satellite viruses, which depend on other viruses, are also considered VoMs.
• Current estimates indicate at least three dozen virus families infecting microorganisms, with some families infecting multiple taxa.

Conclusions:

• VoMs are a diverse and abundant group of genetic entities crucial to microbial ecosystems.
• The study of VoM diversity is ongoing and subject to new discoveries and taxonomic assignments.
• Understanding VoM diversity is essential for comprehending microbial community dynamics and evolution.