| In this study, we evaluated the differences in pearl production and growth traits of thefifth-generation selected lines (F5), the control stocks and the common cultured stocks,calculated the correlation between pearl production and growth traits of the three stocksand related genes, then cloned and analyzed the four growth genes. The results aresummarized as follows:1. Cultured for210days after nucleus-inserting operation,compared pearl productiontraits of the three groups:(1) Compared to the control stocks and the common culturedstocks, survival rate of F5increased by8.79%and7.61%, respectively.(2) Compared tothe control stocks and the common cultured stocks, nuclear retention rate of F5increasedby47.94%and46.06%, respectively, significant difference (P <0.05).(3) Compared to thecontrol stocks and the common cultured stocks, weight of pearl of F5increased by22.02%and18.75%, respectively, the difference was not significant; Compared to the controlstocks and the cultured stocks, pearl thickness of F5increased by30.24%and24.28%,respectively, significant difference (P <0.05);2. Cultured for210days after nucleus-inserting operation. Correlation analysis showedthat the correlation between NACREIN, MSI60, PIF177and pearl traits (pearl weight andpearl thickness) were positive, with correlation coefficients ranging from0.408to0.979.The correlation coefficients between N19and pearl traits were negative, correlationcoefficients of N19and pearl thickness and weight of pearl were-0.214and-0.270,respectively.3. Four growth related genes, transforming growth factor receptor type I (TβR I),epidermal growth factor receptor (EGFR), growth hormone-induced transmembraneprotein (GHITM) and fibroblast growth factors (FGF18) were selected in the experiment.Correlation coefficients between each of the four genes and growth traits of P. martensiiwere calculated. The results showed a positive correlation between eight growth traits of P.martensii and the four genes, with correlation coefficients ranging from0.387to0.998.The correlation coefficient of TβR I and shell length was significant (r=0.998, P <0.05).4. Full-length cDNA of TβR I was2210bp, ORF of1569bp, encoding522amino acids,precursor protein includes a signal peptide, extracellular domain, transmembrane domainand the intracellular domain. Extracellular domain contained an activin type I receptor,intracellular domain includes GS domain (189-215aa) and serine/threonine kinase domain (217-508aa). Full-length cDNA of EGFR was4934bp, ORF of4269bp, encoding1422amino acids. The protein consisted of the extracellular domain of the N-terminal, atransmembrane domain and the intracellular domain of the C-terminal. Extracellulardomain was a ligand binding site, transmembrane domain includes22amino acidresiducing, the receptor anchored in the cell membrane, intracellular domain contains atyrosine kinase domain (872-1128aa). Full-length cDNA of GHITM was1468bp, ORF of1017bp, encoding338amino acids, there was a region same with Bax1-I family.Full-length cDNA of FGF18was2534bp, ORF of714bp, encoding237amino acids,protein precursors had an N-terminal signal peptide structure. The mature protein consistedof213amino acid residues, co-existence of conserved sequences at the45-178aa withFGF family. Amino acid sequence homology compared found TβR I, GHITM and EGFRwas conserved, homology in the mollusks and vertebrates was high. FGF18had relativelypoor conservation. RT-PCR detected the gene expression in the tissues of P. martensii.Four genes were expressed in various tissues and expression in hemocytes was the lowest.TβR I and EGFR expression were highest in gill and foot, while GHITM and FGF18expression in gonad was significantly higher than in the other tissues (P <0.05). |
PDF Full Text Request