The genome of a persistent giant algal virus encodes an unprecedented number of genes involved in energy metabolism

Viruses on Earth are tremendously diverse in terms of morphology, functionality, and genomic composition. Over the last decade, the conceptual gap separating viruses and cellular life has tightened because of the detection of metabolic genes in viral genomes that express complex virus phenotypes upon infection. Here, we describe the 1.4 MB linear genome of Virus RF01 (PkV RF01), a large alga-infecting virus of the family with a unique morphology, an atypical infection profile, and an unprecedented number of genes involved in energy metabolism (such as the tricarboxylic acid cycle (TCA) cycle and the -oxidation pathway). We show that the gene corresponding to one of these enzymes (the succinate dehydrogenase subunit A) is transcribed during infection and is widespread among marine viruses. This discovery provides evidence that a virus can actively regulate energy metabolism with its own gene.