Aquatic virus diversity accessed through omic techniques: A route map to function

Viruses are arguably the simplest form of life yet they play a crucial role in regulating planetary processes. From shuttling genes to ‘lubricating’ microbial loop dynamics, viruses are integral in shaping microbial ecology. In every environment on Earth the role of viruses goes far beyond the simple infect–replicate–kill cycle. Their enormous abundance and seemingly infinite diversity provide the vital clues to the true function of viruses. New ‘omic’ approaches are now allowing researchers to gain extraordinary insights into virus diversity and inferred function, particularly within aquatic environments. The development of molecular markers and application of techniques including microarrays, metagenomic sequencing and proteomic analysis are now being applied to virus communities. Despite this shift towards culture-independent approaches it has proved difficult to derive useful information about infection strategies since so much of the sequence information has no database matches. Future advances will involve tools such as microarrays to help determine the functionality of unknown genes. Sequence information should be considered as a starting point for asking questions and developing hypotheses about the role of viruses. It is an exciting new era for virus ecology and when used in combination with more traditional approaches, virus genomics will give us access to their ecological function on an unprecedented scale.