Viruses of Microorganisms: What are They and Why Care?
Paul Hyman and Stephen T. Abedon
from: Viruses of Microorganisms (Edited by: Paul Hyman and Stephen T. Abedon). Caister Academic Press, U.K. (2018) Pages: 3-14.
Like microorganisms generally, the notion of viruses of microorganisms, or VoMs, that is, viruses that infect cellular microorganisms, is an artificial concept, and particularly so from a phylogenetic perspective. Microorganisms are collectively defined by a single, somewhat primitive phenotype - their smallness even at maturity - rather than together making up a monophyletic taxon. There is, therefore, no clade Microorganisms. As individual viruses are more likely to infect organisms which in fact are members of the same clade, VoMs too do not collectively form a single viral clade, nor even a collection of distinct, only microorganism-infecting taxa. VoMs instead consist of viruses of domains Bacteria, Archaea, and Eukarya, with especially the viruses of Eukarya tending to be evolutionarily related between those that infect eukaryotic microorganisms and those that infect eukaryotic macroorganisms. By contrast, all viruses of domains Bacteria and Archaea represent VoMs. All members of those two domains in fact are microorganisms, though even here, these VoMs are far from being collectively monophyletic. The result, ultimately, is a great deal of diversity among both VoMs and their hosts. In this chapter we introduce the concept of viruses of microorganisms. We also offer a first-approximation introduction to what VoMs exist, as considered in great detail in subsequent chapters read more ...