Photosystem I gene cassettes are present in marine virus genomes

Itai Sharon*, Ariella Alperovitch, Forest Rohwer, Matthew Haynes, Fabian Glaser, Nof Atamna-Ismaeel, Ron Y. Pinter, Frédéric Partensky, Eugene V. Koonin, Yuri I. Wolf, Nathan Nelson, Oded Béj

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

159 Scopus citations


Cyanobacteria of the Synechococcus and Prochlorococcus genera are important contributors to photosynthetic productivity in the open oceans. Recently, core photosystem II (PSII) genes were identified in cyanophages and proposed to function in photosynthesis and in increasing viral fitness by supplementing the host production of these proteins. Here we show evidence for the presence of photosystem I (PSI) genes in the genomes of viruses that infect these marine cyanobacteria, using pre-existing metagenomic data from the global ocean sampling expedition as well as from viral biomes. The seven cyanobacterial core PSI genes identified in this study, psaA, B, C, D, E, K and a unique J and F fusion, form a cluster in cyanophage genomes, suggestive of selection for a distinct function in the virus life cycle. The existence of this PSI cluster was confirmed with overlapping and long polymerase chain reaction on environmental DNA from the Northern Line Islands. Potentially, the seven proteins encoded by the viral genes are sufficient to form an intact monomeric PSI complex. Projection of viral predicted peptides on the cyanobacterial PSI crystal structure suggested that the viralĝ€"PSI components might provide a unique way of funnelling reducing power from respiratory and other electron transfer chains to the PSI.

Original languageEnglish
Pages (from-to)258-262
Number of pages5
Issue number7261
StatePublished - 10 Sep 2009


FundersFunder number
Israel Science Foundation
Technion-Israel Institute of Technology


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