Transcriptome and Biomineralization Responses of the Pearl Oyster Pinctada fucata to Ocean Acidification and Ocean Warming

To elucidate how does the gene expression profiles of whole transcriptome of P.fucata response to seawater acidification and warming, we have employed microarray as a tool to identify gene responses in these stress.The pearl oysters were added into the tanks with the maintaining conditions of temperature 25 °C and 31 °C, acidity pH7.8 and pH7.5, salinity 33‰ in recirculating seawater. The temperatures and pH values in the studies were near future levels and predicted for 2100 and 2300. Adult Pinctada fucata used in this study were obtained from the Marine Biology Research Station in Leizhou Bay, China. Prior to use, the P. fucata were pre-cultured for one week at 19 ± 0.5 °C, pH 8.1 ± 0.05 and salinity 33±0.5‰ in glass aquaria filled with artificial seawater (Formula Grade A Reef Sea Salt, Formula, Japan). After the acclimation period, the organisms with similar size (6-7 cm length) were assigned to 50 L tanks and subjected to the CO2 and temperature stresses, respectively. The P. fucata were maintained for 72 h in the following conditions: 19 °C, pH 7.8 and salinity 33‰ (group abbreviated as P78); 19 °C, pH 7.5 and salinity 33‰ (P75); 25 °C, pH 8.1 and salinity 33‰ (T25); 31 °C, pH 8.1 and salinity 33‰ (T31). The P. fucata in the pre-culture conditions were used as the control. Each treatment was carried out for three replicates in three independent tanks. Samples from three individuals randomly selected from each tank were pooled together to obtain one biological replicate. The mantle samples were collected and preserved on the hours of 72 after treatments for subsequent studies. All the collected mantles above were snap-frozen in liquid nitrogen, and stored at -80°C.