title: Evidence for a role of viruses in the thermal sensitivity of coral photosymbionts.
abstract: Symbiodinium, the dinoflagellate photosymbiont of corals, is posited to become more susceptible to viral infections when heat-stressed. To investigate this hypothesis, we mined transcriptome data of a thermosensitive and a thermotolerant type C1 Symbiodinium population at ambient (27 °C) and elevated (32°C) temperatures. We uncovered hundreds of transcripts from nucleocytoplasmic large double-stranded DNA viruses (NCLDVs) and the genome of a novel positive-sense single-stranded RNA virus (+ssRNAV). In the transcriptome of the thermosensitive population only, +ssRNAV transcripts had remarkable expression levels in the top 0.03% of all transcripts at 27 °C, but at 32 °C, expression levels of +ssRNAV transcripts decreased, while expression levels of anti-viral transcripts increased. In both transcriptomes, expression of NCLDV transcripts increased at 32 °C, but thermal induction of NCLDV transcripts involved in DNA manipulation was restricted to the thermosensitive population. Our findings reveal that viruses infecting Symbiodinium are affected by heat stress and may contribute to Symbiodinium thermal sensitivity.
authors.affiliation: Centre for Marine Bio-Innovation, The University of New South Wales (UNSW), Sydney, NSW, Australia.|School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, Australia.|Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia.
authors.forename: Rachel Ashley
authors.initials: RA
authors.lastname: Levin
authors.affiliation: Red Sea Research Center, Division of Biological and Environmental Science and Engineering, 4700 King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
authors.forename: Christian Robert
authors.initials: CR
authors.lastname: Voolstra
authors.affiliation: Australian Institute of Marine Science, Townsville, QLD, Australia.
authors.forename: Karen Dawn
authors.initials: KD
authors.lastname: Weynberg
authors.affiliation: Australian Institute of Marine Science, Townsville, QLD, Australia.|School of BioSciences, The University of Melbourne, Parkville, VIC, Australia.
authors.forename: Madeleine Josephine Henriette
authors.initials: MJ
authors.lastname: van Oppen
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000502:physiology*; D057894:Coral Reefs; D004267:DNA Viruses / Q000502:physiology*; D004141:Dinoflagellida / Q000502:physiology / Q000821:virology*; D016679:Genome, Viral; D006358:Hot Temperature; D012328:RNA Viruses / Q000235:genetics / Q000502:physiology*; D012367:RNA, Viral / Q000235:genetics; D013559:Symbiosis / Q000502:physiology*; D013696:Temperature; D059467:Transcriptome
chemical_list: D012367:RNA, Viral