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Abstract Eukaryotic phytoplankton contribute to the flow of elements through marine food webs, biogeochemical cycles, and Earth’s climate. Therefore, how phytoplankton die is a critical determinate of the flow and fate of nutrients. While heterotroph grazing and viral infection contribute to phytoplankton mortality, recent evidence suggests that bacteria-derived cues also control phytoplankton lysis. Here, we report exposure to nanomolar concentrations of 2,3,4,5-tetrabromopyrrole (TBP), a brominated chemical cue synthesized by marine γ-proteobacteria, resulted in mortality of seven phylogenetically-diverse phytoplankton species. A comparison of nine compounds of marine-origin containing a range of cyclic moieties and halogenation indicated that both a single pyrrole ring and increased bromination were most lethal to the coccolithophore,Emiliania huxleyi. TBP also rapidly induced the production of reactive oxygen species and the release of intracellular calcium stores, both of which can trigger the activation of cellular death pathways. Mining of the Ocean Gene Atlas indicated that TBP biosynthetic machinery is globally distributed throughout the water column in coastal areas. These findings suggest that bacterial cues play multiple functions in regulating phytoplankton communities by inducing biochemical changes associated with cellular death. Chemically-induced lysis by bacterial infochemicals is yet another variable that must be considered when modeling oceanic nutrient dynamics.
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This content will become publicly available on February 10, 2026
Viral infection impacts volatile organic compound production in the coccolithophore Gephyrocapsa huxleyi
Abstract Volatile Organic Compounds (VOCs) are a diverse collection of molecules critical to cell metabolism, food web interactions, and atmospheric chemistry. The eukaryotic coccolithophoreGephyrocapsa huxleyi, an abundant coastal eukaryotic phytoplankter, forms massive blooms in coastal upwelling regions, which are often terminated by viruses (EhVs).G. huxleyiproduces organosulfur VOCs such as dimethyl sulfide (DMS) and halogenated metabolites that play key roles in atmospheric chemistry. Here we resolved the role of lytic viral infection by EhV207 on VOC production of the model strainG. huxleyiCCMP374. Our analysis identified 79 VOCs significantly impacted by viral infection, particularly during cell lysis, with sulfur containing VOCs like DMS dominating the profiles. Viral lysis results in a nearly six-fold increase in VOC production and generated a previously unrecognized range of VOCs, including 15 sulfur, 22 nitrogen, 2 phosphorus, 19 oxygen and 17 halogen-containing compounds. These findings reveal that viral infection ofG. huxleyireleases VOCs which are much more diverse than previously recognized. We further show that EhV207 primarily accelerates existing metabolic processes inG. huxleyiand facilitates the release of pre-existing intracellular VOCs rather than inducing novel biochemical pathways. This wide range of VOCs may be produced on a massive scale during coccolithophore bloom-and-bust cycles, with important impacts on coastal biogeochemistry and surface ocean/atmosphere interactions.
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- Award ID(s):
- 1948163
- PAR ID:
- 10645114
- Publisher / Repository:
- bioRxiv
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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