In a controlled two-week warm-up meant to mimic Northeast Atlantic heatwaves, researchers found the mussels’ heat-stress genes rose early and then fell.
A study in Aquaculture Reports tested how pure blue mussels and admixed (hybrid-zone) mussels react to repeated heat stress over time. Mussels from an Irish hybrid zone were exposed in a controlled setting to a two-week temperature regime ranging from 13 to 22 °C, designed to simulate projected Northeast Atlantic heatwaves.
The researchers tracked expression of several stress-related genes—heat shock protein genes (hsp24, hsc71, hsp90) and the antioxidant enzyme sod—before exposure and at 24 hours, 4 days, and 7 days after the heat period. The main signal was for hsp24, which rose most at the first acute time point and then declined later, with gene differences not appearing before the heat stress.
Heat-stress genes shift over time
The study found that hsp24 showed significant induction during the repeated heat-stress regime, with time strongly affecting gene expression. The biggest increase occurred 24 hours after heat exposure, and at later time points (4 and 7 days after), hsp24 expression decreased.
Before heat exposure, the researchers did not observe significant differences among controls, treatments, or genotypes. The work also quantified hsc71, hsp90, and sod expression across the same timepoints, using RT-qPCR and linear mixed-effect models, but the abstract highlights hsp24 as the gene with the clear significant induction pattern.
