Transcription of HSP is usually regulated by HSF1 transcription factor (Pirkkala, Nykänen, & Sistonen, 2001). In our experiment, pa-HSF1 basal expression level was higher in non-stressed PC corals (p = 0.0017) but after the beginning of heat stress, the levels of expression in PC and NPC corals aligned (Figure S2). The expression of pa-HSF1 did not correlate with the expression of pa-HSP70