cDNA cloning and expression analysis of glutaredoxin 3 in black tiger shrimp Penaeus monodon

Glutathione (Grx) is a glutathione-dependent oxidoreductase belonging to the thioredoxin (Trx) superfamily. It maintains redox homeostasis in organisms and plays a significant role in resisting oxidative stress. Nevertheless, Grx-related sequence information and functional validation are greatly inadequate in crustaceans. In this study, the Grx3 of Penaeus monodon (PmGrx3) was cloned. The full-length cDNA of PmGrx3 was 1546 bp, which consists of 113-bp 5′-UTR, 458-bp 3′-UTR, and 975-bp ORF, encoding a 324 amino acid putative protein. The putative PmGrx3 protein was 36.04 kDa with a theoretical isoelectric point of 4.98. Sequence alignment indicated that PmGrx3 had the highest amino acid sequence homology with the Grx3 of Penaeus vannamei at 96.57% and was clustered with the crustaceans. Quantitative real-time PCR (qRT-PCR) analysis revealed that PmGrx3 was detected in all tissues examined, with the highest expression in the muscle, stomach, and testis, as well as the lowest expression in abdominal nerve. In addition, PmGrx3 was expressed during the developmental period and was the most highly expressed in the zygote. Both ammonia-N stress and bacterial infection caused different degrees of upregulation or inhibition of the PmGrx3 expression in the hepatopancreas and gills. The present study indicates that PmGrx3 may be a key oxidoreductase in the defense system of shrimp against environmental stress and pathogen infection.