| In this paper,S.subcrenata was used as the experimental object.We studied the effect of high temperature on S.subcrenata through experimental physiology,tissue section technology and transcriptome sequencing technology.This paper studied the changes of physiology,histology and molecular biology of S.subcrenata after heat shock.This research provides some reference data for scientific breeding of S.subcrenata.The results are as follows:1.We studied upper incipient lethal temperature(UILT50)of S.subcrenata in laboratory.The results showed that the UILT50 of the ark shell in different time periods is28.4~37.52?.The ark shell had a high tolerance to 15~26?.And the thermal tolerance of the ark shell decreases with the increase of heat stress time.2.The effects of changes in temperature on physiological and biochemical activities of Ark shell S.subcrenata were studied in the laboratory.The ark shells were divided into two groups: in one group the ark shell was directly moved into a tank at 19?,23? and 27?,and in the other group the ark shell was slowly exposed to the same temperature at a warming rate of 1?/12 h.The results showed that the oxygen consumption rates and ammonia excretion rates of ark shell were increased first and then decreased with the increase in seawater temperature within the experimental temperature,with the maximal values at 23?.Under the rapid warming pattern,activities of SOD,CAT,ACP,and LSZ increased at first and decreased afterwards in ark shell exposed to high temperature for 96 h and reached the maximum at 6h(P<0.05).There was more obvious effect on physiological and biochemical activities of ark shell under sudden warming than under slow warming.3.The aim of this study is to investigate that the effect of heat shock on microstructure and ultrastructure of gill and hepatopancreas in S.subcrenata.The results showed that gill and hepatopancreas damage worsen as heat shock intensifies.We founded that the epithelia cells dropped,gill cavity swelled,which stored lots of haemocytes,finally the gill broke.The findings of gill ultrastructure showed that the number of secondary lysosome and mitochondrion increase.The microstructure of hepatopancreas cells disrupted and their integrity weakened.4.A total of 35555 unigenes were obtained by the transcriptome sequencing of S.subcrenata,with an average length of 809 bp.There were differences in gene expressionbetween control group and heat-treated group.There were 2754 differentially expressed genes between control group and heat-treated 6h group,among which,2057 genes were up-regulated and 697 genes were down-regulated.There were 7715 differentially expressed genes between control group and heat-treated 12 h group,among which,4076 genes were up-regulated and 3639 genes were down-regulated.There were 3464 differentially expressed genes between control group and heat-treated 24 h group,among which,2080 genes were up-regulated and 1384 genes were down-regulated.5.In this study,225,083 possible SNP were screened from the transcriptome data of S.subcrenata.50297 SNPc and 48510 SNPs were identified in the control and heat-treated group,respectively.And the number of SNP existed in control group only(SNPc-only)was4124,while there were 7104 SNP only existed in heat-treated group(SNPh-only).These GO/KEGG annotated SNP are distributed over 5462 unigenes.GO analysis found that gene SNPc,gene SNPh,gene SNPc-only and gene SNPh-only had the similar proportion in each of molecular function,cellular component,biological process.KEGG analysis found that all four groups of SNP were enriched in endocytosis,phagosome and ubiquitin mediated proteolysis pathways. |
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