LC-MS/MS clams and cockle mantle data

Increased heavy rainfall cause important drops in salinity to values close to 0, which can persist for several days in estuaries. Lethal and sublethal physiological and behavioural effects of decreases in salinity below ten have already been found to occur in the commercially relevant clam species Venerupis corrugata, Ruditapes decussatus and R. philippinarum and the cockle Cerastoderma edule, which generate ~74 million euros annually in Galicia (NW Spain). However, studies of the molecular response to hyposaline stress in bivalves are scarce. This ‘shotgun’ proteomics study evaluates changes in mantle-edge proteins subjected to short-term hyposaline episodes in two different months (March and May) during the gametogenic cycle. We found evidence that the effects of the gametogenic cycle on the proteome are greater than those related to the salinity treatments. However, hyposalinity modulated proteome profiles for both months in V. corrugata and C. edule and on R. philippinarum in May, involving proteins implicated in ROS production, redox homeostasis, cytoskeleton modulation and the activation of apoptotic, autophagic and lipid degradation pathways. Nevertheless, essential proteins for an optimal osmotic stress response but high energy demandants, such as chaperones, osmoprotectants and DNA repair factors, were in both large and small abundance under hyposalinity for those species. In both time points for R. decussatus and R. philippinarum in March, almost no differences between treatments were detected. These exploratory results reinforce the interest in the specific study and conservation of native species C. edule and V. corrugata, particularly sensitive to hyposalinity.