Stress response in naturally acclimatized corals correspond to
experimentally preconditioned corals
In vitro experiments may not always reflect the natural behavior
of the organism. To analyze the stress response of naturally
acclimatized corals, we collected six Pocillopora acuta colonies
living in the outdoor flow-through tanks (WT) at the beginning of
September 2019, when water temperatures peaked 29ºC in Kaneohe bay (Fig.
S2). We let them acclimate to winter ambient 26ºC to simulate our
preconditioning experiment and then exposed them to acute heat stress
(32ºC). The correlation of gene expression between WT and PC corals
during acute heat stress was surprisingly high (Fig 3, S2) showing that
corals react to peaking temperatures in a similar way as to natural
temperature profile. It also suggests that during summer, when the risk
of extreme weather causing warming events and mass coral bleaching is
the highest, corals naturally acclimatize to warm temperatures through
modulations in the PCD pathways, which increase their survival chances
by slowing down the bleaching rate.