Conference Proceeding
Spatio-temporal changes in expression of hsp70 and hsp90 genes in the branching coral Acropora muricata
Rising sea surface temperature, as a result of global
warming, in combination with high light intensity is a
prominent cause of widespread coral bleaching. The
vulnerability of corals to bleaching tends to be highly
variable within geographical locations, between and even
within cnidarian genera resulting in differential bleaching
patterns. Such differential bleaching susceptibility
has been attributed to host and/or symbiont factors in
response to environmental conditions. Of these responses,
in-situ variation of the expression of genes involved in
heat responses remains to be thoroughly studied. In this
study, we examined spatial and seasonal variation in gene
expression of the coral heat shock proteins (Hsps), hsp70
and hsp90, by quantitative real-time PCR, in Acropora
muricata colonies that harbor Symbiodinium clade A,
along a coast-reef scale in Belle Mare lagoon, Mauritius
in 2014. The lagoon is characterized by coast-reef scale
(< 1 km) differences in daily thermal fluctuation and
light intensity. A. muricata colonies closer to the shore
experience comparable maximum temperatures, but
daily temperature variation was 2-fold greater compared
to the reef colonies. The A. muricata colonies at these two
sites also have different bleaching histories as bleaching
of A. muricata colonies occurred only at the reef site
during the 2009 bleaching event. Results show that both
during summer and winter, coast colonies had higher
expression of the hsp70 gene compared to reef colonies.
Contrarily, coast colonies showed less hsp90 expression
compared to reef colonies both in summer and winter. In
winter, both hsp70 and hsp90 transcript levels were lower
than in summer, in both coast and reef colonies. These
observations suggest that the expression of Hsps genes
in A. muricata varied both spatially and seasonally under
the influence of prevailing environmental conditions.
Furthermore, results may imply potential involvement of
hsp70 gene in local acclimatization in A. muricata and
thus may possibly explain in part the previously reported
differential bleaching pattern at this coast-reef scale.
Published: 28 July 2017
Copyright: Copyright: © 2017 Yohan D. Louis. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.