Transcriptomic analysis provides insight into the mechanism of salinity adjustment in swimming crab Portunus trituberculatus.

Abstract

Low salinity is one of the main factors limiting the distribution and survival of marine species. As a euryhaline species, the swimming crab (Portunus trituberculatus) is adaptive to relatively low salinity. However, the mechanisms underlying salinity stress responses in P. trituberculatus is not very clear. The primary objective of this study was to describe the salinity adaptation mechanism in P. trituberculatus. The crabs were exposed to low salinity stress, and gill tissue was sampled at 0, 12, 36, 48 and 72h and subjected to high throughput sequencing. Subsequently, we tested the accuracy and quality of the sequencing results, and then carried out GO and KEGG bioinformatics on the differentially expressed genes (DEG). Each sample yielded more than 1.1Gb of clean data and 23 million clean reads. The process was divided into early (0-12h), middle (12-48h), and late phase (48-72h). A total of 1971 (1373 up-regulated, 598 down-regulated), 1212 (364 up-regulated, 848 down-regulated), and 555 (187 up-regulated, 368 down-regulated) DEGs with annotations were identified during the three stages, respectively. DEGs were mainly associated with lipid metabolism energy metabolism, and signal transduction from the three stages, respectively. A substantial number of genes were modified by salinity stress, along with a few important salinity acclimation pathways. This work provides valuable information on the salinity adaptation mechanism in P. trituberculatus. In addition, the comprehensive transcript sequences reported in this study provide a rich resource for identification of novel genes in this and other crab species.