Virus-induced spore formation as a defense mechanism in marine diatoms

Angela Pelusi, Pasquale De Luca, Francesco Manfellotto, Kimberlee Thamatrakoln, Kay D. Bidle, Marina Montresor

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Algal viruses are important contributors to carbon cycling, recycling nutrients and organic material through host lysis. Although viral infection has been described as a primary mechanism of phytoplankton mortality, little is known about host defense responses. We show that viral infection of the bloom-forming, planktonic diatom Chaetoceros socialis induces the mass formation of resting spores, a heavily silicified life cycle stage associated with carbon export due to rapid sinking. Although viral RNA was detected within spores, mature virions were not observed. ‘Infected’ spores were capable of germinating, but did not propagate or transmit infectious viruses. These results demonstrate that diatom spore formation is an effective defense strategy against viral-mediated mortality. They provide a possible mechanistic link between viral infection, bloom termination, and mass carbon export events and highlight an unappreciated role of viruses in regulating diatom life cycle transitions and ecological success.

Original languageEnglish (US)
Pages (from-to)2251-2259
Number of pages9
JournalNew Phytologist
Issue number4
StatePublished - Feb 2021

All Science Journal Classification (ASJC) codes

  • Physiology
  • Plant Science


  • Chaetoceros socialis
  • diatoms
  • life cycle
  • resting spores
  • single-stranded RNA virus


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