The Hidden Impact of Viruses
Metaorganisms have evolved for more than 500 million years, yet only recently have advances in sequencing technology allowed us to appreciate the full nature of the complexities in host–microbe interactions. These technological advances have revealed that in addition to bacteria and associated eukaryotic symbionts, one more important player is an integral member of the holobiont: viruses (Fig. 10.1). Viruses are found anywhere cellular life exists, in any environment or ecosystem. They exist along with their hosts as part of a dynamic community ensemble of exogenous viral particles and endogenous proviruses. Yet, although being the most abundant and diverse biological component on the planet, comparatively little is known about their role in the holobiont. Does the virome play a role in establishing and maintaining the microbiome? What are the underlying mechanisms as to how viruses control microbes? Can bacteriophage-based therapies be used in invertebrates such as corals for treating complex disorders?