Rapid shifts in thermal reaction norms and tolerance of brooded coral larvae following parental heat acclimation

Abstract

Thermal priming of reef corals can enhance their heat tolerance; however, the legacy effects of heat stress during parental brooding on larval resilience remain understudied. This study investigated whether preconditioning adult coral Pocillopora damicornis to high temperatures (29°C and 32°C) could better prepare their larvae for heat stress. Results showed that heat-acclimated adults brooded larvae with reduced symbiont density and shifted thermal performance curves. Reciprocal transplant experiments demonstrated higher bleaching resistance and better photosynthetic and autotrophic performance in heat-exposed larvae from acclimated adults compared to unacclimated adults. RNA-seq revealed strong cellular stress responses in larvae from heat-acclimated adults that could have been effective in rescuing host cells from stress, as evidenced by the widespread upregulation of genes involved in cell cycle and mitosis. For symbionts, a molecular coordination between light harvesting, photoprotection and carbon fixation was detected in larvae from heat-acclimated adults, which may help optimize photosynthetic activity and yield under high temperature. Furthermore, heat acclimation led to opposing regulations of symbiont catabolic and anabolic pathways and favoured nutrient translocation to the host and thus a functional symbiosis. Notwithstanding, the improved heat tolerance was paralleled by reduced light-enhanced dark respiration, indicating metabolic depression for energy | 1099 JIANG et al.

The acute and chronic low-temperature stress responses in Porites lutea from a relatively high-latitude coral reef of the South China Sea

“…Previous studies have shown that apoptotic and antiapoptotic processes coexist within cells (Kvitt et al, 2016;Majerova et al, 2021). The balance between anti-apoptotic and pro-apoptotic genes within the cell dictates the ultimate apoptotic rate (Kvitt et al, 2016;Majerova et al, 2021;Jiang et al, 2023). This also suggests that P. lutea under acute stress at 14°C was in a pre-bleaching stage.…”

Including environmental and climatic considerations for sustainable coral reef restoration

“…Among these reef restoration approaches, branching coral species have emerged as the preferred candidates due to their fast growth rates, higher nursery survival rates, the ease of handling large numbers of fragments in the nurseries, esthetic appeal, and the capacity to quickly create complex environments. Considering future environmental contexts, these reef restoration approaches may be further optimized by incorporating naturally heat-resistant corals [ 103 , 104 ], or those engineered to be more environmentally resilient via selective breeding, coral chimerism, epigenetics, and/or microbiome manipulation [ 105 , 106 ], or by artificially increasing structural complexity [ 107 ]. This optimization can be employed to design reef-of-tomorrow restoration in a degraded coral reef area, featuring a different consortia of coral reef taxa compared to the pre-degradation state.…”