, from the hepatopancreas transcriptome library of was 5 112 bp with an open reading frame of 3 561 bp that encodes 1 186 amino acids. PmRelish protein exhibits the typical architecture of Rel/NF-κB family members, including a conserved N-terminal Rel homology domain (RHD), a nucleus localization signal, six C-terminal ankyrin repeats, and a death domain, suggesting that it belongs to the class I NF- mRNA was constitutively expressed in all detected tissues, with the highest expression in the hemocytes. Using real time PCR, we analyzed the mRNA expression profile of following challenge with a variety of stimuli. The results show that Vibrio vulnificus, Staphylococcus aureus, and WSSV, and significantly up-regulated by . In addition, we confirmed that viral nucleic acid analogue poly(I:C) and R484 activate the expression of gene plays an important role in the immunity of tiger shrimp, and is directly or indirectly involved in the immune response against bacteria and viruses.