Discovery and Classification of the φ6 Bacteriophage: An Historical Review

Abstract

The year 2023 marks the fiftieth anniversary of the discovery of the bacteriophage φ6. The review provides a look back on the initial discovery and classification of the lipid-containing and segmented double-stranded RNA (dsRNA) genome-containing bacteriophage—the first identified cystovirus. The historical discussion describes, for the most part, the first 10 years of the research employing contemporary mutation techniques, biochemical, and structural analysis to describe the basic outline of the virus replication mechanisms and structure. The physical nature of φ6 was initially controversial as it was the first bacteriophage found that contained segmented dsRNA, resulting in a series of early publications that defined the unusual genomic quality. The technology and methods utilized in the initial research (crude by current standards) meant that the first studies were quite time-consuming, hence the lengthy period covered by this review. Yet when the data were accepted, the relationship to the reoviruses was apparent, launching great interest in cystoviruses, research that continues to this day.

Bacteriophages and their unique components provide limitless resources for exploitation

“…Pseudomonas syringae phage ϕ6 was the first enveloped dsRNA Cystovirus identified more than 50 years ago (Gottlieb and Alimova, 2023 ) and has served as the model phage to understand phage RNA biosynthesis, packaging and host lipid bilayer recruitment. Reminiscent of eukaryotic viruses, the phages use protein-triggered membrane fusion for entry into their bacterial hosts (Bamford et al, 1987 ) and the phages exit surrounded by host phospholipid bilayers from the inner membrane (Heymann, 2023 ).…”