Metabolomic analysis of heat-hardening in adult green-lipped mussel (Perna canaliculus): A key role for succinic acid and the GABAergic synapse pathway

For the 'Summer' mussels, metabolite abundances in gill tissues of both naïve and heat-hardened mussels were quantified. For mussels at 33 °C, succinic acid was significantly higher in naïve mussels than heat-hardened mussels, indicating perturbations to mitochondrial pathways in these thermally stressed mussels. Additionally, analysis of biochemical pathway activity suggested a loss of neural control i.e. significantly reduced GABAergic synapse activity, in naïve vs. heat-hardened mussels at 33 °C. Taken together these findings suggest that heat-hardening improves mussel survival at higher temperatures by delaying the onset of cellular anaerobic metabolism, and by maintaining inhibition of neural pathways. Such results offer new perspectives on the complex suite of sub-cellular stress responses operating within thermally stressed organisms.