Cyanobacteria of the genera Synechococcus and Prochlorococcus are important contributors to photosynthetic productivity in the open ocean. The discovery of genes (psbA, psbD) that encode key photosystem II proteins (D1, D2) in the genomes of phages that infect these cyanobacteria suggests new paradigms for the regulation, function and evolution of photosynthesis in the vast pelagic ecosystem. Reports on the prevalence and expression of phage photosynthesis genes, and evolutionary data showing a potential recombination of phage and host genes, suggest a model in which phage photosynthesis genes help support photosynthetic activity in their hosts during the infection process. Here, using metagenomic data in natural ocean samples, we show that about 60 of the psbA genes in surface water along the global ocean sampling transect are of phage origin, and that the phage genes are undergoing an independent selection for distinct D1 proteins. Furthermore, we show that different viral psbA genes are expressed in the environment.
Bibliographical noteFunding Information:
above countries remain part of the genetic patrimony of the country from which they were obtained. This work was supported by a grant from the Israel Science Foundation, a grant from the Israeli Ministry of Science and Technology, an EMBO YIP award (OB), a COBI grant from the Israeli Ministry of Science and Technology (MS), grants from the US Department of Energy Office of Science’s Biological and Environmental Research Program grant and the Gordon and Betty Moore Foundation (J Craig Venter Institute).
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics