BejaLab (@bejalab.bsky.social)

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. ### Competing Interest Statement The authors have declared no competing interest. Secretaría de Ciencia, Humanidades, Tecnología e Innovación, Becas de Posgrado para Maestrías y Doctorados en Ciencias y Humanidades en el Extranjero Natural Sciences and Engineering Research Council of Canada, 2022-03350, 2022-00329 Phycological Society of America, Norma J. Lang Early Career Researcher Fellowship https://www.biorxiv.org/content/10.1101/2025.09.23.678156v1