Metamorphosis Development Process And Whole Transcriptome Analysis Of Epinephelus Fuscoguttatus And Hybrid Offspring

As an important Marine economic fish in our country,grouper is nutritious,delicious meat,widely popular and has very good economic value.With the development of aquaculture industry,its aquaculture scale is expanding year by year.In this study,postsperm development and skeletal development of E.fuscoguttatus and its hybrid,EFT were observed,and whole tissue of E.fuscoguttatus was analyzed by full transcriptome sequencing.1.Study on postgerm development of the E.fuscoguttatus and EFTIn this study,regular samples were taken from E.fuscoguttatus and EFT,and the postsperm development of both species was observed.The results showed that the growth rate of EFT was slightly slower than that of E.fuscoguttatus at the larval stage,but the body weight of EFT was higher than that of E.fuscoguttatus at the larval stage.In addition,the mortality rate of EFT is lower than that of E.fuscoguttatus.At 2-20 days of age,the total length of EFT is very little different from that of E.fuscoguttatus.At 23 days of age,E.fuscoguttatus has suffered serious seedling loss and a large number of fry died.Under the same feeding conditions,EFT did not show this phenomenon,which may be attributed to the disease of E.fuscoguttatus,which leads to a large number of fry death.During this period,the surviving fry were highly resistant to disease and had the nature to eat each other,which led to the rapid growth of E.fuscoguttatus and its total length began to be larger than that of EFT.However,at the age of 4 months,the gap between the total length of EFT and E.fuscoguttatus narrowed sharply,with the total length of E.fuscoguttatus being 9.2cm and EFT 10.2cm.At the age of 5 months,the weight of the EFT was 32.7g with a total length of 12.6cm,while the E.fuscoguttatus was 29.7g with a total length of 11.2cm.The above results indicate that under the same breeding conditions,EFT grows faster than its mother,and has a low mortality rate during growth,so it has excellent heterosis,which can be used for large-scale breeding.2.Study on the skeletal development of E.fuscoguttatus and EFTFry of EFT and E.fuscoguttatus were sampled regularly and stained with both scleroid-cartilage.The results showed that there was little difference in the sequence of skeletal development between EFT and E.fuscoguttatus.The newly hatched larvae had no skeleton,and the skull developed from 5DAH and lasted 43 days.Development of the spine begins at 11 DAH and is completed at 38 DAH.The appendages of the two species are pectoral fin,dorsal fin,ventral fin,caudal fin and anal fin.At 5DAH,pectoral fin development begins.At 48 DAH,pectoral fin ossification is completed in EFT,and pectoral fin ossification is completed in E.fuscoguttatus at 43 DAH.At 8DAH,dorsal fin and pelvic fin developed,the second dorsal fin spine of EFT and E.fuscoguttatus began to extend continuously at 11 DAH,the second dorsal fin spine of EFT began to degrade at 26 DAH,and shrank to the shortest at 38 DAH.The second dorsal fin spines of brown spotted grouper undergo degeneration at 20 DAH and shorten to the shortest at 43 DAH.Then the caudal fin develops.Anal fin development begins at 11 DAH,anal fin ossification is completed in 43 DAH EFT and 48 DAH E.fuscoguttatus.The caudal fins of both fish developed at 8DAH,and the caudal fin of EFT was ossification first than that of E.fuscoguttatus.In addition,during the development of caudal fin,the number of caudal bones of EFT after fusion was 3,which is the same as that of most grouper.However,when the caudal fin ossification was completed,there were 4 caudal bones,one more than that of EFT.3.Correlation analysis of mRNA and lncRNA in dorsal and ventral fin development of E.fuscoguttatusAt present,there are few reports on the gene regulation of coronal spine elongation and contraction of grouper during development.In order to explore this phenomenon,whole transcriptome sequencing analysis was conducted on whole tissues of E.fuscoguttatu,and the analysis results showed that 23,960 DEGs were expressed.After WGCNA analysis,the corresponding modules were selected for GO functional annotation and KEGG enrichment analysis.GO is enriched to pathways that are significantly enriched in metabolic pathways,including Autophagy,Wnt signaling pathway,cell adhesion molecules and TGF-beta signaling pathway signaling pathway),etc.Through association analysis with lncRNAs,the results showed that there were 39 relational pairs,including 23 mRNAs and 3 lncRNAs.The association network diagram showed three functional LncRNAs: MSTRG.23534.1,MSTRG.33437.1,MSTRG.36322.2.Meanwhile,the results showed that 22 mRNA genes,including WNT3,WNT9 B,BMP4 and LRP2,were positively correlated with lncRNA expression.It is speculated that WNT3 and WNT9 B may interact with lncRNA MSTRG.23534.1 in the process of osteogenic differentiation to promote the role of Wnt signaling pathway in osteogenic differentiation,in view of the phenomenon of elongation and contraction of coronal spine.lncRNA MSTRG.23534.1 plays a role with BMP4 in regulating osteogenic differentiation through the BMP-smad signaling pathway.Low density lipoprotein receptor associated protein LRP2 was also positively correlated with lncRNA MSTRG.23534.1 and lncRNA MSTRG.33437.1,which played a related role in osteogenic differentiation of E.fuscoguttatus.