The Genetic Diversity Analysis Of Breeding Population By SSR, Screening Of Molecular Markers Of Cold Tolerance And The Expression Of Cold Tolerance Genes Cirp Of Large Yellow Croaker (Pseudosciaena Crocea)

Large yellow croaker Pseudosciaena crocea, belong to Perciformes, Sciaenidae, Pseudosciaena, is a kind ofimportant seawater fish which are breeding by net cage. Owing to the low temperature of seawater of Zhejiang Province in winter, almost every year many large yellow croakers have been freezed to death and thefarmers had to undertake the economic lose more or less. This study took the genetic diversity analysis bySSR, screened the molecular markers of cold tolerance and cloned the CIRP which is kind of cold-tolerancerelated gene and detected its the expression in the circumstance of cold intimidate.The results of genetic diversity showed that the content of polymorphism information of breeding group is0.681,0.657and0.596respectively. It showed that it’s genetic diversity was higher and have the potentialof further breeding. But it also needs to be protected and avoids the lose of genetic diversity. And theaverage number of allele of two different cold tolerance groups of breeding group is4.454~4.546, themean observation and the expected hetrozygosities is0.677~0.685and0.653~0.661respectively. Thecontent of polymorphism information is0.591~0.601. It revealed the genetic diversity of two groups wason the comparable level. The mean observation and the expected hetrozygosities, and it indicated that thecharacter differences of cold tolerance group maybe not lead to the genetic differentiation.The results of SSR revealed marker KPC43amplified2significant difference alleles (the length offragment is170bp and150bp respectively) in two groups of large yellow croaker. The frequency of170bpfragment in the cold tolerance group is significant higher than in the cold sensitive group. It showedprominent positive correlation with the cold tolerance and the correlation index is0.498**. The frequencyof150bp fragment in the cold sensitive group is significant higher than in the cold tolerance group. Itshowed prominent negative correlation with the cold tolerance and the correlation index is-0.417**. Allthis indicated two alleles maybe have certain linkage relationship with some kind of cold tolerance genes.Compared the gene sequence of two alleles found that the KPC43170bp have10(TG) reduplicates morethan KPC43150bp in the core sequence. According to the study, we can infer that the lose of TGreduplicates of no-cold-tolerance individual maybe lead to the inactivation of cold tolerance gene.The results of gene cloning showed the cDNA full-length of CIRP is1211bp (contain polyA), and theopen reading frame code182amino acids. RT-PCR showed that the CIRP expressed in many tissues oflarger yellow croaker. In liver, spleen, brain and muscle have higher expression, and in intestine and gillhave lower expression. qRT-PCR revealed the expression of CIRP increased along with the time extensionof cold intimidate. In the initial stage (0.5h) the expression had no obvious variation, and at4h it reachedit’s peak and had obvious difference with the control group (P<0.05). All this revealed that the CIRP is kindof cold tolerance gene.All the study can provide theoretical foundation for the breeding of cold tolerance large yellow croaker,and also provide reference for the further breeding of more cold tolerance breed.