betaprophage

Betaprophage is a term used in bacteriological literature to describe bacteriophages that infect Betaproteobacteria, a diverse class of Gram-negative bacteria within the phylum Proteobacteria. In many accounts, betaprophages are temperate phages capable of establishing lysogeny by integrating their genome into the host chromosome to form a prophage, though strictly lytic betaprophages are also described. The host range of betaprophages is typically restricted to Betaproteobacteria, with occasional cross-infectivity reported in closely related taxa.

Genomes of betaprophages are usually modular, encoding functions for DNA replication, structural proteins, lysis, and integration. The integration step is often mediated by an integrase enzyme and specific attachment sites (att). Prophages can be induced by stress conditions, leading to excision, replication, and production of new virions. Some betaprophages carry accessory genes that can alter host metabolism, stress responses, or virulence, facilitating horizontal gene transfer within Betaproteobacteria.

Ecology and importance: Betaprophages contribute to the genetic and ecological dynamics of Betaproteobacteria in soil, freshwater, and clinical environments. They influence bacterial population structure, drive gene exchange, and can impact the behavior and adaptability of their hosts. Because many Betaproteobacteria are difficult to culture, many betaprophages remain unidentified, and discovery relies on metagenomic and culture-based methods with modern phage isolation techniques.

See also: bacteriophage, prophage, temperate phage, Betaproteobacteria.