Proteomics analysis of Pacific oyster (Crassostrea gigas) under acute and longer-term chronic salinity stress treatment as examined by label-free mass spectrometry

Abstract

Salinity plays an important role in the environmental adaptability of Pacific oysters (Crassostrea gigas), whereas the molecular regulation mechanism of the organism responding to acute and longer-term chronic salinity stress remains unknown. In the present study, the proteome of C. gigas under acute salinity stress (exposed to the given salinity directly for 3 days) and longer-term chronic salinity stress (exposed to gradually changing salinity at a rate of one unit per day until the given salinity was reached and the total duration of exposure was one month) was quantitatively compared using sequential window acquisition of all theoretical fragment ion mass spectra (SWATH-MS). SWATH-MS data of 880 proteins were subjected to chemometric differentiation analysis, and 55 proteins were selected as differentiators responding to acute and longer-term chronic salinity stress. Most of the differentiating proteins (DPs) were attributed to cellular components by Gene Ontology (GO) annotation analysis. Additionally, mRNA expression of the DPs measured by real-time polymerase chain reaction (RT–PCR) verified similarities and differences in the expression level between mRNA and protein, whereas some tendencies were meaningful for mechanistic understanding. The proteins glutathione S-transferase, histone H2B, and thymosin β were finally suggested as biomarkers of C. gigas exposed to salinity stress.