Embryonic Hormetic Priming Modulates Later-Life Thermal Tolerance

Area of Science:

• Marine Biology
• Climate Change Adaptation
• Ectotherm Physiology

Background:

• Climate change poses risks to marine ectotherms, particularly those near their thermal limits.
• Developmental plasticity is a key adaptive trait for aquatic organisms facing ocean warming.
• The molecular basis of developmental plasticity in response to thermal stress is not well understood.

Purpose of the Study:

• To investigate the capacity of early-life thermal priming to modify later-life thermal tolerance in the black-lip pearl oyster (Pinctada margaritifera).
• To explore the family-specific effects of developmental plasticity on thermal performance.
• To identify molecular mechanisms underlying thermal memory and stress response.

Main Methods:

• Two bi-parental progenies of Pinctada margaritifera were subjected to early developmental thermal priming (28°C vs. 32°C) during embryogenesis (3-24 hpf).
• Oysters were subsequently raised under common conditions (28°C) for four months.
• Thermal tolerance and molecular responses (heat stress, Unfolding Protein Response) were assessed at a sublethal temperature (34°C) using a network-preservation approach.

Main Results:

• Early thermal priming induced family-specific effects, enhancing thermal tolerance in one family and reducing it in another.
• Core molecular pathways for heat stress response were conserved across families and unaffected by priming.
• Subtle environmental memory was observed through network reorganization, particularly in gene regulatory pathways of the Unfolding Protein Response (UPR).

Conclusions:

• Developmental thermal priming can have contrasting, family-dependent impacts on oyster thermal tolerance.
• While core heat stress pathways are conserved, network-level changes suggest a form of environmental memory.
• Further research with refined protocols is needed to harness hormetic priming for aquaculture and conservation efforts.