A Novel Iridovirus Discovered in Deep-Sea Carnivorous Sponges

Carnivorous sponges (family Cladorhizidae) use small invertebrates as their main source of nutrients. We discovered a novel iridovirus (carnivorous sponge-associated iridovirus, CaSpA-IV) in Chondrocladia grandis and Cladorhiza oxeata specimens collected in the Arctic and Atlantic oceans at depths o...

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Bibliographic Details
Published in:Viruses
Main Authors: Marta Canuti, Gabrielle Large, Joost T. P. Verhoeven, Suzanne C. Dufour
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2022
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Online Access:https://doi.org/10.3390/v14081595
https://doaj.org/article/36235da3d0a648f68568820923df4b2c
Description
Summary:Carnivorous sponges (family Cladorhizidae) use small invertebrates as their main source of nutrients. We discovered a novel iridovirus (carnivorous sponge-associated iridovirus, CaSpA-IV) in Chondrocladia grandis and Cladorhiza oxeata specimens collected in the Arctic and Atlantic oceans at depths of 537–852 m. The sequenced viral genome (~190,000 bp) comprised 185 predicted ORFs, including those encoding 26 iridoviral core proteins, and phylogenetic analyses showed that CaSpA-IV is a close relative to members of the genus Decapodiridovirus and highly identical to a partially sequenced virus pathogenic to decapod shrimps. CaSpA-IV was found in various anatomical regions of six C. grandis (sphere, stem, root) from the Gulf of Maine and Baffin Bay and of two C. oxeata (sphere, secondary axis) from Baffin Bay. Partial MCP sequencing revealed a divergent virus (CaSpA-IV-2) in one C. oxeata . The analysis of a 10 nt long tandem repeat showed a number of repeats consistent across sub-sections of the same sponges but different between animals, suggesting the presence of different strains. As the genetic material of crustaceans, particularly from the zooplanktonic copepod order Calanoida, was identified in the investigated samples, further studies are required to elucidate whether CaSpA-IV infects the carnivorous sponges, their crustacean prey, or both.