Effects Of High Temperature On Serum Biochemical Index And Screening Relevant SNP Markers In Large Yellow Croaker Larimichthys Crocea

Serum cortisol,blood glucose and lactic acid content were investigated in 8-month-old Larimichthys crocea exposed to high temperature?33??for 2 h.Thermal tolerance to high water temperature was evaluated in 2-month-old Larimichthys crocea by slowly heating?rising from 25?to 36??.A genome-wide association study was performed to screening relevant SNP markers using specific-locus amplified fragment sequencing?SLAF-seq?technology in thermal-tolerant and thermal-sensitive group.The main results as fellows:1.When subjected to high temperature?33??for 2 h,compared with the control group?23??,the content of serum cortisol,blood sugar and serum lactic acid was significantly increased?P<0.01 or 0.05?.According the results above mentioned,serum cortisol,blood glucose and lactic acid can be used as important index of large yellow croaker exposed to high temperature.2.Twenty thermal-tolerant and twenty thermal-sensitive individuals were sequenced using the Illumina HiSeq^TM2500 sequencing platform.A total of 98,620,785 paired-end reads raw data were obtained,Q₃₀0 value was 84.71%on average,the average GC content was 43.10%.The SOAP2 software was used to map paired-end reads onto the reference genome of L.crocea.Paired-end reads that could be mapped to the reference genome were retained for analysis.We compared paired-end sequences with the reference genome sequence and defined the SLAF label using the group with an average depth of sequencing?2 in line with the comparison error correction result.A total of 146,560 SLAF were identified with an average read depth of 10.26 in the study population.Plink software?v1.07?was used for data quality control.SNP with low call frequencies?<85%?and low minor allele frequencies?<5%?were rejected.We detected SNP among the defined SLAF fragments,identifying 419,211 SNPs were eligible for inclusion in the genome-wide association analysis after quality control measures.The TASSEL-compressed GLM model was used to do association analysis,thirty-eight significant SNPs was identified to be associated with thermal tolerance trait?P<2.39E-08?.The nucleotide sequences corresponding to the SNPs were compared by Blastx against the genome of Larimichthys crocea to screen genes and 28 candidate genes were obtained.These results provide basic information to develop thermal-tolerant lines of Larimichthys crocea using marker-assisted selection breeding in the future.