Meeting Abstract
Blue mussels (Mytilus edulis) are a keystone species in coastal marine communities. Protracted decreases in nearshore salinity as a result of global climate change pose a threat to the survival, distribution, and abundance of mussels; accurate predictions about how mussel populations will be impacted by changing salinity requires an improved understanding of how this species responds to salinity stress. Mussels are osmoconformers and numerous studies have shown that adult mussels mitigate low salinity stress through regulation of intracellular osmolytes, principally through efflux of free amino acids. However, little is known about the genetic regulation of this osmotic stress response in mussels, and thus we have incomplete knowledge of the mussels’ capacity to acclimatize or adapt to a changing environment. Furthermore, mussels have a complex life-history; larvae are generally more sensitive to environmental stressors but few, if any, studies have investigated the degree to which the osmotic stress response is conserved among life history stages. Based on microarray data, we have selected two genes that are differentially expressed in adult mussels exposed to hyposaline stress and likely play an important role in the regulation of free amino acids. Using rt-qPCR, we have monitored the time-specific variation in expression of these genes in adult and larval mussels exposed to a 33% drop in salinity for 72 h. Concurrently, we used NMR spectroscopy to examine variation at the cellular level by measuring changes in the relative concentrations of free amino acids. Our results indicate that the interactions between gene expression and cellular-level phenotype during hypoosmotic exposure are complex and that the responses are stage-, tissue-, and time-specific.
