Archive | 2019
Bacteria–Virus Interactions
Abstract
Viruses that infect bacteria (bacteriophages) are ubiquitous and abundant in the environment. In marine ecosystems, viruses may infect as much as 20–40% of the bacterial population. Therefore, viruses play important roles in global biogeochemical cycle. Viruses also affect the genome evolution and fitness of their host microorganisms through horizontal gene transfer. On the other hand, viruses may also acquire metabolic genes from their hosts and temporally manipulate host metabolism during infection through the expression of specialized “auxiliary metabolic genes.” In addition, host-selective viral infection is believed to maintain bacterial diversity via frequency-dependent selection, whereby virus infection reduces bacterial species that have become relatively abundant in a population and thereby allows coexistence of multiple host–virus combinations. Further, continual bacteria–virus interactions drive reciprocal evolution of bacterial defense and viral counterdefense mechanisms (coevolution), resulting in increased diversity. Thus, examination of bacteria–virus interactions is essential for understanding microbial evolution and diversity.