Bacterial Quorum-Sensing Signal Arrests Phytoplankton Cell Division and Impacts Virus-Induced Mortality
Scott B. Pollara, Jamie W. Becker, Brook L. Nunn, Rene Boiteau, Daniel J. Repeta, Miranda C. Mudge, Grayton Downing, Davis Chase, Elizabeth L. Harvey, Kristen E. Whalen
Abstract
Bacteria and phytoplankton form close associations in the ocean that are driven by the exchange of chemical compounds. The bacterial signal 2-heptyl-4-quinolone (HHQ) slows phytoplankton growth; however, the mechanism responsible remains unknown. Here, we show that HHQ exposure leads to the accumulation of DNA damage in phytoplankton and prevents its repair. While this effect is reversible, HHQ-exposed phytoplankton are also relieved of viral mortality, elevating the ecological consequences of this complex interaction. Further results indicate that HHQ may target phytoplankton proteins involved in nucleotide biosynthesis and DNA repair, both of which are crucial targets for viral success. Our results support microbial cues as emerging players in marine ecosystems, providing a new mechanistic framework for how bacterial communication signals mediate interspecies and interkingdom behaviors.