Host–virus dynamics in a natural
coccolithophore population
05 November 2012
PML scientists have been involved in an
exciting new research study which examines phytoplankton cell fate
as a result of viral infection.
Phytoplankton are the basis of marine foodwebs
and are responsible for nearly half the global primary production.
The coccolithophore Emiliania huxleyi is a common
species of phytoplankton and has an integral role in marine
foodwebs. When conditions are favourable, coccolithophores have the
capacity to form significant annual blooms. Viruses are
now considered a major force in terminating these blooms.
Viruses are the most abundant biological
entities in the marine environment and are incredibly important
because of their significant role in controlling
phytoplankton and bacterial populations and recycling
nutrients. Until relatively recently there has been very little
understanding of the relationship between Emiliania
huxleyi and its virus (EhV) in the natural
environment.
This study was conducted during a mesocosm experiment in
Norwegian coastal waters organised by PML, which was set up to
investigate host-virus interactions during a natural E.
huxleyi bloom. The main aim of this current research was to
determine the molecular mechanisms controlling phytoplankton
host-virus interactions and the associated cell fate.
Recently published laboratory studies
demonstrated viral sphingolipid-based regulation of host-virus
interactions through the induction and control of the
host's programmed cell death (PCD) machinery. Here we assessed
whether this molecular mechanism could also be observed in
natural phytoplankton-virus populations and thus, potentially
serve as a promising biomarker of viral infection.
This study is the first of its kind to
investigate natural phytoplankton host-virus interactions at
subcellular levels of resolution, and uses a diverse suite of
molecular tools and in situ fluorescent staining to target
different subcellular processes.
The results provide the first demonstration of
PCD activation in natural populations and support the role of
glycosphingolipids and programmed cell death in regulating E.
huxleyi–EhV interactions.
PML scientist Dr Susan Kimmance was involved
in the experimental research and analysis concerning viral-induced
stress and mortality of E. huxleyi.
The results not only provide further
mechanistic understanding of the regulation of natural host–virus
interactions, but also a promising foundation for using unique
lipid-based proxies and molecular biomarkers to quantify and
constrain the influence of viral infection in the oceans.