Observation Of Gonad Development Cycle And Expression Pattern Of Related Gene LpCullin2 In Larimichthys Polyactis

Gonadal development is an important part of fish developmental biology research,in recent years,Larimichthys polyactis has been faced with problems such as low age,precocious puberty and miniaturization.Therefore,it has become a very important research idea and direction to carry out the research on the reproductive biology,artificial breeding and increasing culture technology of L.polyactis.In order to further enrich the practical technology of artificial culture of L.polyactis,more detailed basic data of gonad development of L.polyactis were obtained.This study was mainly elaborated from two aspects: First,tissue sections of L.polyactis at different development stages were observed by staining with hematoxylin-eosin(HE)staining solution;Secondly,the open reading frame of Lp Cullin2 gene was cloned,and the expression of Lp Cullin2 gene in different tissues and gonad development stages of L.polyactis was analyzed by fluorescence quantitative PCR.The main results are as follows:1、This article mainly use H.E solution to look at the development of L.polyactis,aims to understand the development organization in the process of change,to grasp the propagation law of L.polyactis,enrich its biological data,improve the artificial breeding technology provides the necessary scientific support,and also provides a reference for the basic research of other Sciaenidae.Through the study,it is found that the gonads of L.polyactis have periodic changes,and the annual change trend of GSI of female and male is basically the same,but there are differences between female and male in the value and change range of GSI index,and the female will be significantly higher than the male.The gonad development of L.polyactis can be divided into six stages.The spawning type is partly synchronous spawning,and the reproductive cycle is one year,and the main breeding period is April to May.2、By cloning the open reading frame of the Lp Cullin2 gene,The length of the gene was 3080 bp and encoded 745 amino acids.The results of multiple sequence alignment,protein three-dimensional structure diagram and phylogenetic tree showed that Cullin2 gene was highly conserved in different species and phylogenetic evolution.In order to further understand the expression of Cullin2 in L.polyactis,it was tested by real-time fluorescence quantitative PCR,the intestine,blood,testis,ovary,muscle,head,kidney,brain,liver,heart,gill and spleen of L.polyactis were tested.The results showed that Lp Cullin2 gene was expressed in intestinal tract,blood,testis,ovary,muscle,head kidney,brain,liver,heart,gill and spleen,but the relative expression of Lp Cullin2 gene was the highest in testis and ovary,and the lowest in intestinal tract.At the same time,the relative expression levels of Lp Cullin2 in testis and ovaries at different time were detected,and the results showed that the relative expression levels of Lp Cullin2 were different at different time.The relative expression levels of Lp Cullin2 were higher in January and lower in August and September.