Effects of Salinity Stress on the mRNA Expression of PRL and Na+-K+-ATPase 1 of Turbot (Scophthalmus maximus)

Abstract:

Turbot (Scophthalmus maximus) is an economically important species extensively cultured in China. In this study, we exerted acute salinity stress on turbot to identify their response in the expression of certain genes including prolactin (PRL) and Na+-K+-ATPase a1 in the intestine and gill. Relative mRNA expression of PRL and Na+-K+-ATPase a1 in four salinity groups (salinity 5, 10, 40, 50) and a control group (salinity 30) were tested using quantitative real-time PCR. Sampling of the control group conducted at 5 h, 12 h, 24 h, 53 h, and 102 h. Data analysis demonstrated that the two genes expressed in all tissues in a spatio and time specific pattern. Over the time, the relative mRNA expression of intestinal PRL and Na+-K+-ATPase a1 firstly increased and then decreased under the stress of salinity 5 and 50. The expression of PRL mRNA in the gill firstly increased and then decreased under salinity 50; under the same salinity, the expression of Na+-K+-ATPase a1 mRNA showed a reversed pattern which was a decrease followed by an increase. Compared to the control group, the mRNA expression of Na+-K+-ATPase a1 in the gill did not change significantly under salinity 5. In the intestine, the mRNA expression of the two genes were highly synergic, and they both firstly increased and decreased along with the increase of salinity, and the correlation coefficient was close to 1. However, there was an obvious antagonistic effect between the two genes in the gill under salinities 10 to 40. When the expression of PRL rose/fell, the expression of Na+-K+-ATPase a1 declined/rose, and the correlation coefficient was negative. This confirmed that PRL could inhibit the Na+-K+-ATPase activity. Our study provided theoretical information in the turbot gene regulation mechanism in response to salinity stress.