Analysis Of Gonad Tissue Structure And Gonad Transcriptome In Cherax Quadricarinatus Of Different Sexes

The mechanism of gender determination and differentiation has always been a hot issue in the field of crustacean reproduction and development.Obtaining a single sex breeding population through gender control is an effective way to increase breeding yield.Understanding the physiological characteristics of different gender groups of breeding objects is an important prerequisite for constructing gender regulation techniques.Redclaw crayfish(Cherax quadricarinatus)is one of the important freshwater economic shrimp species in China,with a complex sex composition.Intersex,which can simultaneously have a bisexual reproductive system,is a unique model for studying sex regulation in crustaceans.In order to analyze the physiological structure differences of redclaw crayfish of different sexes,understand the process of gonadal differentiation,and explore the genes and pathways related to the balance of female and male reproductive systems in the intersex redclaw crayfish,and then explore the formation mechanism of intersex.In this study,the karyotype of female and male redclaaw crayfish was analyzed to determine whether there are heterotypic sex chromosome.Using paraffin section technology to analyze the gonadal differentiation node of redclaw crayfish,and to clarify the structural characteristics of the gonadal tissues of adult male,female,and intersex redclaw crayfish.Transcriptome sequencing was performed on the gonadal tissues of female,male and intersexual redclaw crayfish,and candidate genes related to the balance of female and male reproductive systems of intersex redclaw crayfish were preliminarily screened.The main results were as follows:1.The number of female and male redclaw crayfish chromosomes is 200,the karyotype formula is n=100=36m+33sm+14st+17t,and no heterotypic sex chromosome is found;2.The node of gonadal differentiation of the larvae is about twice molting.The histological morphology of testis and androgenic gland,spermatogenesis of the intersex redclaw crayfish is the same as those of the male.The ovarian development period of the intersex redclaw crayfish is the same as that of the slow growing ovary of female.3.A total of 9033 differentially expressed genes were identified between the intersex gonads and the gonads of male and female redclaw crayfish.Among them,the number of differentially expressed genes between the intersex gonads and male gonads was the highest(8690).The KEGG annotation indicates that differentially expressed genes are mainly enriched in metabolic and insulin resistance pathways,indicating that the bisexual reproductive balance of intersex redclaw crayfish may be achieved through metabolic regulation.In summary,this study identified the chromosomal karyotype formula of redclaw crayfish,clarified the key node of gonadal differentiation in redclaw crayfish,and preliminarily screened candidate genes related to the balance of male and female reproductive systems in intersex redclaw crayfish,providing important theoretical references for the study of gender regulation mechanism in redclaw crayfish.