A growing number of recent studies show the involvement of two evolutionarily conserved programmed cell death (PCD) pathways in coral bleaching – apoptosis and autophagy/symbiophagy (Downs et al., 2009; Dunn, Schnitzler, & Weis, 2007; Fujise et al., 2013; Hawkins, Krueger, Becker, Fisher, & Davy, 2014; Kaniewska et al., 2012; Kvitt, Rosenfeld, & Tchernov, 2016; Pernice et al., 2011; Ros et al., 2016; Tchernov et al., 2011; Yu, Huang, Zhou, Tang, & Yu, 2017). They may occur independently but often simultaneously interact or compensate for each other (Denton & Kumar, 2019; Dunn et al., 2007).  For example, the key pro-survival genes Bcl-2 (B-cell lymphoma 2) and BI-1(Bax inhibitor 1) inhibit both apoptosis and autophagy, and pro-death genes BAX (Bcl2 Associated X) and BAK (Bcl2 Antagonist/Killer) activate themin vertebrate systems (Castillo et al., 2011; Karch et al., 2017; Xu et al., 2013).