Comparative Study On Response To Hypoxia Stress In Different Families Of Litopenaeus Vannamei Based On Proteomics

Litopenaeus vannamei is one of the highest production and important economic value prawn species in China.Because of its high growth rate,strong environmental tolerance,strong disease resistance,low demand for feed protein,long living duration out of the water and delicious meat,it has become one of the most widely cultivated shrimp varieties in the worldwide.The cultivation of L.vannamei occupies an extremely important position in China’s aquaculture industry.In recent years,due to the discharge of anthropic wastewater,the greenhouse effect and extreme weather,the frequency of hypoxia has continued to increase,which has seriously affected the healthy development of L.vannamei.At present,the researches on hypoxia stress of L.vannamei mainly focus on physiological responses or the roles of some single gene under the hypoxia stress.There are few studies on the mechanism of hypoxia stress responses to L.vannamei by protcomics,especially for the muscle tissue.In this study,the physiological biochemical responses,differential protein expression,and the expression characteristic of the related crucial functional protein genes in different families of L.vannamei were studied.These results can help to reveal the hypoxia stress mechanism.The main findings are as followings:In this experiment,there was no significant (P <0.05) change in the number of Total hemocyte counts (THC) in the two families of L.vannamei after 3 h hypoxia.After hypoxia for 6 h and for 12 h,hypoxia stress was significantly (P <0.05).The THC in the shrimp,and the number of THC in the hypoxic sensitive family decreased more.Hypoxic treatment had no significant (P> 0.05) effect on the Hemocyanin concentration (HC) of the two families,and there was no significant difference between the two families in the hypoxia period (P> 0.05).The overall trend is rising of HC in the two families,which indicated that hypoxia stress could significantly reduce the number of THC of L.vannamei and affect the HC.Based on the Data-Independent Acquisition (DIA) analysis,3,417 differential proteins were detected.Among them,29 differential expression were down regulated and 244 expressions were up regulated after hypoxia for 12 hours in the hypoxia sensitive family.Additionally,10 differential proteins were down regulated and 25 expressions were up regulated after hypoxia for 12 h in the hypoxia-tolerant family.The results shown that the differentially expressed proteins arc play critical roles in immune response,energy metabolism,cytoskcleton construction,molecular chaperones,and others.In hypoxia stress,the expression of the above functional proteins related genes are significantly different,and which can be used as biomarkers for hypoxia stress in L.vannamei.Five crucial functional genes were selected for uncovering the expression characteristics under the hypoxia stress via quantitative real-time PCR analysis,which were related to the differential proteins in proteomic experiments,including Hcmocyanin,Chitinase,Heat Shock Protein 90 (HSP 90),Programmed Death Protein (PDCD),and Glycogen Phosphorylase (GP).These results showed that the genes expression were consistent with proteomic experimental data,except for PDCD and GP.Due to the complex post-transcriptional modification mechanisms involved in the translation of mRNA into proteins,which generates the difference between the expression of mRNA and protein levels in organisms,the detail mechanism need further research to explore.