![\"A](\"https:\/\/www.europesays.com\/uk\/wp-content\/uploads\/2025\/08\/a-giant-virus-wags-its.jpg\" "\\"Tail")
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Tail attachment. Scanning (SEM) and transmission (TEM) electron micrographs of the Pelagodinium PelV1 system at the early stages of infection. Credit: bioRxiv (2025). DOI: 10.1101\/2025.07.19.665647<\/p>\n
University of Hawai’i at M\u0101noa oceanographers have identified PelV-1, a dinoflagellate-infecting giant virus whose micron-length tail reaches 2.3 \u00b5m, stretching current notions of viral architecture.<\/p>\n
Few phytoplankton-infecting viruses have been characterized, and dinoflagellate isolates remain scarce, leaving ocean-ecosystem models short of vital host-virus data. Prior surveys listed only two large DNA viruses infecting Heterocapsa species, neither accompanied by a genome sequence<\/a>.<\/p>\n In the study, “A dinoflagellate-infecting giant virus<\/a> with a micron-length tail<\/a>,” published<\/a> on the bioRxiv pre-print server, researchers combined electron microscopy<\/a> and high-coverage sequencing to characterize PelV-1 infection of Pelagodinium sp.<\/p>\n Host cultures originated from Station ALOHA in the North Pacific Subtropical Gyre, where water sampled at 25 m yielded both the dinoflagellate and its virus.<\/p>\n Microscopy documented ~200 nm capsids and five morphotypes distinguished by two appendages: a 30 nm-wide tail extending up to 2.3 \u00b5m and a shorter, thicker protrusion positioned opposite a stargate capsid opening.<\/p>\n Time-series electron microscopy showed tails used for initial attachment but mature virions inside cells are non-tailed, supporting post-lysis tail assembly.<\/p>\n Results place PelV-1 and the rare co-PelV within Mesomimiviridae and detail 467 coding sequences plus nine tRNAs in PelV-1, alongside 569 genes and 14 tRNAs in co-PelV. Annotated genes span amino-acid, carbohydrate, lipid and TCA-cycle metabolism, light-harvesting complex, rhodopsin, ion channel, sugar transporters, aquaporin, tail-fiber homologs and encode cold-shock protein HSP70.<\/p>\n The authors propose that a 2.3 \u00b5m tail enhances host-encounter rates in the low-biomass gyre, inviting future work on how such structures shape plankton ecology.<\/p>\n PelV-1’s record-setting tail and broad metabolic arsenal expand the morphological and genomic diversity known for marine viruses.<\/p>\n \n Written for you by our author Justin Jackson<\/a>, edited by Sadie Harley<\/a>, and fact-checked and reviewed by Robert Egan<\/a>\u2014this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive.
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