The Molecular Mechanism Research Of Peroxiredoxin Involved In Regulating The Innate Immune Of Procambarus Clarkii

The Procambarus clarkii culture industry is one of important mainstay industry at the coastal region in China.In recent years,the marine culture industry,which represented by P.clarkii culture,has developed rapidly.However,various diseases caused by pathogenic microorganisms have brought huge losses to the aquaculture industries.How to improve the disease resistance of cultured species is an important issue in the current aquaculture industry.Crustaceans are rely mainly on the innate immune system to defend themselves against pathogens.Therefore,it is important and necessary to study the innate immunity mechanism of shrimp to provide theoretical reference and technical support for shrimp disease control.In this study,the full length c DNA of the peroxiredoxin 4 gene（Prx 4）was obtained based on transcriptome sequencing of P.clarkii.Bioinformatics analysis showed that Pc-PRX 4 was conserved among different species and had signal peptide sequences.Pc-Prx 4 was expressed at a relatively high level in heart of P.clarkii by q RT-PCR.The expression levels of Pc-Prx 4 was obviously up-regulated in different tissues after challenged with Vibrio harveyi.At the same time,the H₂O₂levels were significantly enhanced in hepatopancreas and gill tissues.Through gene cloning,protein purification and other related technologies,it was found that Pc-PRX 4 in vitro recombinant protein can protect DNA molecules from ROS damage,and the r Pc-PRX 4 showed antioxidant activity.Finally,when the Pc-Prx 4 was knockdown by RNAi,H₂O₂level in P.clarkii increased abnormally when V.harveyi was not injected.The H₂O₂content in P.clarkii after V.harveyi injection was higher than that without V.harveyi injection,and the survival rate of P.clarkii was increased.However,genes related to melanization pathway,reactive oxygen species pathway,apoptosis pathway and Toll pathway were up-regulated.In addition,after knockdown of Pc-Prx 4 and injection of V.harveyi followed by the injection of antioxidant NAC,H₂O₂level in P.clarkii was significantly reduced,and the survival rate of P.clarkii decreased.At the same time,genes related to melanization pathway,apoptosis pathway and toll pathway were down-regulated.The above results showed that,Pc-PRX 4 is an important regulatory enzyme in the antioxidant system of P.clarkii.Meanwhile,it can regulate the level of H₂O₂to affect the innate anti-bacterial immune response of P.clarkii.This study clarified the important role of Pc-PRX 4 in the innate immunity response of P.clarkii.and found the H₂O₂can regulate toll pathway,melanization pathway and apoptosis pathway.This is an important basic theory complement to the antibacterial innate immunity response in invertebrates,also provides a scientific basis for the prevention and control of bacterial diseases of P.clarkii.