A giant virus infecting green algae encodes key fermentation genes

• Published in: Virology (New York, N.Y.) N.Y.), 2018-05, Vol.518, p.423-433
• Main Authors: Schvarcz, Christopher R., Steward, Grieg F.
• Format: Article
• Language: English
• Subjects: Algal virus; Auxiliary metabolic genes; Giant virus; Green algae; Mimiviridae; NCLDV; Pyruvate formate-lyase
• ISSN: 0042-6822; 1096-0341
• DOI: 10.1016/j.virol.2018.03.010

The family Mimiviridae contains uncommonly large viruses, many of which were isolated using a free-living amoeba as a host. Although the genomes of these and other mimivirids that infect marine heterokont and haptophyte protists have now been sequenced, there has yet to be a genomic investigation of a mimivirid that infects a member of the Viridiplantae lineage (green algae and land plants). Here we characterize the 668-kilobase complete genome of TetV-1, a mimivirid that infects the cosmopolitan green alga Tetraselmis (Chlorodendrophyceae). The analysis revealed genes not previously seen in viruses, such as the mannitol metabolism enzyme mannitol 1-phosphate dehydrogenase, the saccharide degradation enzyme alpha-galactosidase, and the key fermentation genes pyruvate formate-lyase and pyruvate formate-lyase activating enzyme. The TetV genome is the largest sequenced to date for a virus that infects a photosynthetic organism, and its genes reveal unprecedented mechanisms by which viruses manipulate their host's metabolism. •A large green alga-infecting virus was isolated from seawater and sequenced.•The genome is the largest described for a virus infecting a photosynthetic organism.•The virus appears to form a chlorophyte-infecting clade in the family Mimiviridae.•This is the first report of fermentation-related genes in a virus.