Complementary DNA (cDNA) cloning and expression analysis of selenium glutathione peroxidase (Se-GPx) and glutathione S-transferases (GST) 1 in red claw crayfish (Cherax quadricarinatus).

Selenium glutathione peroxidase (Se-GPx) and Glutathione S-transferases (GST) are crucial parts of cellular detoxification systems that protect cells from reactive oxygen species (ROS). In this study, cDNA sequences of CqGST1 and CqSe-GPx were cloned from red claw crayfish (Cherax quadricarinatus). The molecular masses of the predicted protein are 25.36 and 21.49 kDa, respectively. CqGST1 and CqSe-GPx have open reading frames (ORFs) of 657 bp and 570 bp and encode peptides of 218 and 189 amino acids, respectively. Sequence alignment showed that the amino acid sequence of CqSe-GPx identity with that of the Exopalaemon carinicauda, Penaeus japonicus, Macrobrachium rosenbergii, Penaeus monodon, Litopenaeus vannamei, Macrobrachium nipponense and Scylla paramamosai. The amino acid sequence of CqGST1 identity with Procambarus clarkii, Stegastes partitus, Gavialis gangeticus, Alligator mississippiensis, and L. vannamei. The qRT-PCR results showed that CqSe-GPx and CqGST1 were found in a variety of tissues, with the highest hemolymph expression and the weakest expression in muscle, eye stalk, and heart. The expression levels of CqSe-GPx and CqGST1 in the hepatopancreas and gills of crayfish were detected under ammonia-N and microcystins-LR stresses. The expression of CqSe-GPx was induced in the hepatopancreas of crayfish during MC-LR stress, and gill CqSe-GPx expression levels were induced at 6 and 12 h. Hepatopancreas and gill CqSe-GPx expression levels were significantly up-regulated during ammonia-N at 24 and 48 h, respectively. The CqGST1 expression levels were significantly elevated in the hepatopancreas and gill during MC-LR or ammonia-N stress. Under ammonia stress, hepatopancreas and gill GST expression levels of crayfish showed a decreasing and then increasing trend. Hepatopancreas and gill CqGST1 expression levels of crayfish were significantly up-regulated at 12, 24, and 48 h of ammonia-N stress. These results suggest that CqSe-GPx and CqGST1 play an important role in protecting C. quadricarinatus from ammonia-N and MC-LR stress and provide a theoretical basis for further study on the molecular mechanism of response to environmental stress on crayfish.