Repository logo
 

Molecular Responses to Thermal and Osmotic Stress in Arctic Intertidal Mussels (Mytilus edulis): The Limits of Resilience.

Published version
Peer-reviewed

Change log

Authors

Barrett, Nicholas J  ORCID logo  https://orcid.org/0000-0003-1920-9704
Thyrring, Jakob 
Harper, Elizabeth M 
Sejr, Mikael K 
Sørensen, Jesper G  ORCID logo  https://orcid.org/0000-0002-9149-3626

Abstract

Increases in Arctic temperatures have accelerated melting of the Greenland icesheet, exposing intertidal organisms, such as the blue mussel Mytilus edulis, to high air temperatures and low salinities in summer. However, the interaction of these combined stressors is poorly described at the transcriptional level. Comparing expression profiles of M. edulis from experimentally warmed (30 °C and 33 °C) animals kept at control (23‱) and low salinities (15‱) revealed a significant lack of enrichment for Gene Ontology terms (GO), indicating that similar processes were active under all conditions. However, there was a progressive increase in the abundance of upregulated genes as each stressor was applied, with synergistic increases at 33 °C and 15‱, suggesting combined stressors push the animal towards their tolerance thresholds. Further analyses comparing the effects of salinity alone (23‱, 15‱ and 5‱) showed high expression of stress and osmoregulatory marker genes at the lowest salinity, implying that the cell is carrying out intracellular osmoregulation to maintain the cytosol as hyperosmotic. Identification of aquaporins and vacuolar-type ATPase transcripts suggested the cell may use fluid-filled cavities to excrete excess intracellular water, as previously identified in embryonic freshwater mussels. These results indicate that M. edulis has considerable resilience to heat stress and highly efficient mechanisms to acclimatise to lowered salinity in a changing world.

Description

Keywords

blue mussel, cellular stress response, salinity, thermal tolerance, transcriptome, acclimation, freshening, climate change, aquaporins

Journal Title

Genes (Basel)

Conference Name

Journal ISSN

2073-4425
2073-4425

Volume Title

13

Publisher

MDPI AG