Molecular characterization of three peroxiredoxin genes in Portunus pelagicus expressed in response to Vibrio alginolyticus challenge

Portunus pelagicus inhabits coastal muddy or sandy seabed, and are often exposed to rotten sewage containing a large number of bacteria. In this study, RT-PCR technology was used to clone peroxiredoxin (prx) genes prx1, prx3 and prx6 of P. pelagicus. Genes expressed in normal tissue, gills and hepatopancreas after Vibrio alginolyticus stress were tested by RT-qPCR. The full-length coding sequences of prx1, prx3 and prx6 were 597 bp, 690 bp and 660 bp, which encode 198, 229 and 219 amino acids, respectively. Prx1 and prx3 are typical 2-cys peroxir-edoxins, while prx6 is a typical 1-cys peroxiredoxin. RT-qPCR revealed widespread expression of prx1, prx3 and prx6 in all the tested tissues, and their expression was the highest in gills (93.81-fold vs muscle tissue), hepa-topancreas (28.95-fold vs thoracic ganglia) and gonads (219.43-fold vs thoracic ganglia), respectively. The highest expression of prx1, prx3 and prx6 in the hepatopancreas of surviving individuals belonging to the experimental group were 1.67-, 1.86-and 2.11-fold higher than the control group after V. alginolyticus challenge, and the highest expression in gills was 5.99-, 5.51-and 6.11-fold higher than in the control group, respectively. However, the expression of prx genes in dead individuals of the experimental group was lower than the surviving individuals. These results revealed that prx genes play an important role in the defense against V. alginolyticus stress. The cause of death under sublethal concentration may be related to the regulation of prx genes expression.