Membrane lipid metabolism, heat shock response, and energy costs mediate the interaction between acclimatization and heat hardening response

Thermal plasticity on different timescales, including acclimation/acclimatization and heat hardening response – a rapid adjustment for thermal tolerance after a nonlethal thermal stress, can interact on organisms to improve the resilience to thermal stress. However, little is known about the physiological mechanisms mediating this interaction. To investigate underpinnings of heat hardening responses after acclimatization in warm season, we measured thermal tolerance plasticity, compared transcriptomic and metabolomic changes after heat hardening at 33 or 37oC followed by recovery of 3 h or 24 h in an intertidal bivalve Sinonovacula constricta. The clams showed explicit heat hardening responses after acclimatization in warm season. The higher inducing temperature (37oC) caused a less effective heat hardening effect than the inducing temperature that was closer to seasonal maximum temperature (33oC). Metabolomic analysis highlighted the elevated contents of membrane glyceropholipids in al...