Viruses of Microbes

Viruses of microbes encompass all viruses that infect archaea, bacteria, and single-celled eukaryotes, especially algae and protozoa. Bacteriophages, the name given by Félix d’Herelle to bacterial viruses, were initially studied for their bactericidal properties to treat infectious diseases, before the discovery of antibiotics. During the second half of the 20th century, these viruses were used as tools to decipher the molecular mechanisms of cellular processes giving birth to molecular biology. Following the golden age of bacteriophage research, microbial viruses, including the more recently discovered viruses of archaea and protists, experienced a renaissance when they were found in many diverse ecosystems. Over the past two decades, the advancement of viral ecology has led to the realization that viruses of microbes are the most abundant biological entities on earth and play a major regulating role in ecosystems. They are recognized as chief contributors to horizontal gene flow and drivers of evolution. In addition, being key predators of cyanobacteria and algae in oceans, they impact global warming and climate change. Thus, viruses of microbes play a pivotal role in evolution, ecology, health, and environmental science.