Identification Of Three Antioxidant Emergency Protein Genes From Scapharca Subcrenata As Well As Its Expression Under The Single Or Composite Stress Of Benzopyrene And Cadmium

The catalase gene(CAT),the metallothionein(MT)and the heat shock protein(HSP90)are three kinds of antioxidant emergency immune genes commonly found in organisms.CAT is considered to be a special marker under heavy metal stress.In addition,MT is a small molecule protein widely rich in cysteine(Cys)in living organisms,which has the ability to bind metal ions,and can effectively regulate the balance of metal ions in living cells,thus having the function of scavenging free radicals,detoxifying heavy metals and other functions.HSP90 acts on many target proteins to keep the intracellular environment stable when the body cells are stimulated by temperature and environmental factors.Scapharca subcrenata were widely distributed in Japan and China.The resources in the shallow waters such as Laizhou Bay,Bohai Bay,Liaodong Bay and Haizhou Bay are particularly abundant.In recent years,Scapharca subcrenata are suffering from diseases caused by various environmental changes,including various heavy metal pollution and organic pollution,which ultimately lead to serious economic losses of the Scapharca subcrenata.Based on the current culture background of Scapharca subcrenata,the full-length cDNAs of three antioxidant-related genes,CAT,MT and HSP90,were cloned,and the expression of corresponding three genes in Scapharca subcrenata under cadmium and benzopyrene stress was analyzed.Fill in the research gaps of these three antioxidant genes in the bivalve,and provide application guidance for the improvement of culture technology in the face of organic pollutants and heavy metal pollution.Specific research results are as follows:In this study,the full-length cDNAs of CAT,MT and HSP90 genes were obtained by RACE technology in Scapharca subcrenata,Among them: SsCAT protein full-length cDNA is 2145 bp,including 650 bp 5'-UTR region,1118 bp 3'-UTR region,ORF region is 1482 bp in length,deduced to encode 493 amino acids;SsMT protein cDNA is 816 bp in length,including 158 bp 5'-UTR region,685 bp 3'-UTR region,ORF region is 231 bp in length,deduced to encode 76 amino acids;SsHSP90 protein cDNA is 2613 bp in length,including 281 bp 5'-UTR region,1435 bp 3'-UTR region.,the ORF region is 2187 bp in length,which is deduced to encode 728 amino acids.These three antioxidant genes share highly similar homology in other species.Under the stress of cadmium and benzopyrene,the three antioxidant genes were analyzed by Q-PCR technique,found the difference in expression between mixed stress and single stress.With the increase of stress time,the mixed stress of cadmium and benzopyrene exhibits different synergistic or antagonistic effects on the expression of the three genes.These results indicated that different immune genes have different immune responses to environmental stimuli,and the three immune genes respectively can be used as pattern recognition molecules,and play a role in the innate immunity of bivalve to heavy metals and organic pollution.Moreover,these results contributes to the breeding selection and production of Scapharca subcrenata.