A jumbo cyanophage encodes the most complete ribosomal protein set in the known virosphere

Viruses encode ribosomal proteins (RPs), but their genomes usually harbor a single RP-coding gene. Here, we reannotate the genome of the jumbo cyanophage PhiMa05 and show that it encodes six RPs, an RP acetyltransferase, and a ribosome biogenesis protein. Evolutionary analyses suggest that these viral RP-coding genes may have been horizontally transferred to certain members of the Vampirovibrionia, a non-photosynthetic basal lineage of Cyanobacteriota, via integration of the viral genome.