Spatial variation of thermal resistance and stress protein expression in Stylophora pistillata from tropical and subtropical Taiwan

Coral reefs have been extensive and accelerating degradation worldwide probably due to a continuous global warming since industrial revolution. One of the causes for global coral degradation is “coral bleaching”, a syndrome known as loss of symbiotic algae (dinoflagellate genus Symbiodinium), the algae pigment, or both. In the last decades, much attention has been focused on diversity of Symbiodinium phylotypes identified by ribosomal RNA gene, and their potential functions on resistance and resilience of coral reefs to heat stress. Previous results indicated that the cellular defense mechanisms may be attributed to the physiological response to the stress in coral hosts or in conjunction with symbiotic algae. In this study, Stylophora pistillata collected from Penghu, Yeliu, and the elevated temperature water outlet of the third nuclear plant in Kenting (NUKE) was used as the model coral to examine the thermal resistance and acclimatisation. Our result reveals that thermal acclimatisation resulted thermal resistance in S. pistillata collected from NUKE are higher than that from Yeliu and Penghu Island and corals expressed more Hsp70 in the samples from NUKE than that from Yeliu and Penghu. Symbiodinium cells showed more contribution on thermal resistance than host cells in this study. The role of sub-clade typing of the Symbiodinium in these corals required further examination.