Abstract
Global coral reef decline is driven in large part by the breakdown of the coral-algal symbiosis during temperature stress. Corals can acclimatize to higher temperatures, but the cellular processes underlying this ability are poorly understood. We show that preconditioning-based improvements in thermal tolerance in Pocillopora acuta are accompanied by increases in host glutathione reductase (GR) activity and expression, which prevents DNA damage. We found a strong correlation between GR and BI-1 expression in heat-stressed preconditioned corals and discovered an antioxidant response element (ARE) in the GR promoter, suggesting BI-1 could regulate GR expression through the Nrf2/ARE pathway. To fortify this link, we developed an siRNA-mediated gene knockdown protocol and targeted the coral BI-1 gene. BI-1 knock-down decreased glutathione reductase expression and activity, and increased oxidative DNA damage in heat-stressed preconditioned corals, showing that enhanced regulation of antioxidant response during acute heat stress is a key mechanism that prevents oxidative DNA damage after preconditioning.
Teaser Preconditioning improves redox homeostasis and prevents oxidative stress in a thermally stressed reef-building coral
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
The methodology section was updated to clarify individual methods, mostly the siRNA-mediated gene knockdown. We added experiments supporting the siRNA specificity (Figure S3 and the corresponding text in Results and Discussion sections). Figures 2 and S1 were revised to increase the clarity of the results.