Local acclimatisation-driven differential gene and protein expression
patterns of Hsp70 in Acropora muricata: implications for coral
resistance to bleaching
Abstract
Corals show spatial acclimatization to local environment conditions. The
various cellular mechanisms involved in local acclimatization and
variable bleaching patterns in corals remain to be thoroughly
investigated. In this study, the modulation of a protein involved in
cellular heat stress tolerance, the Heat shock protein 70 (Hsp70), was
compared at both gene expression and protein level in Acropora muricata
colonies from two contrasting environments, in the lagoonal system of
Belle Mare (Mauritius), having differential bleaching susceptibilities.
The relative Hsp70 levels varied significantly between colonies from the
different environments, colonies having different health status and the
year of collection. Before the bleaching event of 2016, near-coast
colonies had higher basal levels of Hsp70 gene and protein compared to
back reef colonies. During the bleaching event, the near-coast colonies
did not bleach and had significantly higher relative levels of Hsp70
compared to bleached back reef colonies. The A. muricata colonies
investigated had genetically identical host genotype and were hosting
the same Symbiodiniaceae genus (Symbiodinium) irrespective of habitat
and sampling year. These findings provide further evidence of the
involvement of Hsp70 in conferring bleaching resistance to corals.
Understanding of these processes is paramount for improvement of
conservation efforts, where Hsps could potentially be used as proactive
biomarkers for heat stress in corals.