Studies On Transcriptomes Of Mantle And Pearl Sac And Expression Of Biomineraliazation Genes In The Pinctada Fucata Martensii

The pearl oyster, Pinctada fucata martensii, is not only a important marine bivalve species for production of artificial free pearl, but also an ideal animal for studies of molecular mechanism under biomineralization. In this study, in order to screen genes related to biomineralization, we sequenced and characterized transcriptomes of the P. fucata martensii mantle and pearl sac using454pyrosequencing, Besides, the expression levels in mantle and and their correlation with phenotypic traits of pearl oyster were also characterized for four mineralization gene based on analysis of eight families of P. fucata martensii. The results showed that:1. A total of25,723unique transcripts were assembled from220,824quality reads for the the transcriptomes of the mantle tissue. Besides,146unique transcript segments homologous to49reference biomineralization genes were identified, including calcineurin-binding protein, amorphous calcium carbonate binding protein1, calmodulin, calponin-like protein, carbonic anhydrase1, Glycine-rich shell matrix protein, Lysine-rich matrix protein, mantle gene or protein, nacrein, pearlin, PIF,’ regucalcin and shematrin. Moreover,10,285potential single nucleotide polymorphism (SNP) loci and7,836putative Indels were also screened from the transcriptomes of the mantle.2.21,729putative unique transcripts were assembled from186158high quality reads.23candidate biomineralization genes were identified, such as calmodulin, calponin-like protein, mantle gene, pearlin, nacrein and PIF. Besides, the sequence data contained4,303potential single nucleotide polymorphism loci and4,291prabable INDELS, providing a resource for molecular biomarker, population genetics and gene function. There was very significant difference of the expression levels in mantle among the eight families of P. fucata martensii for the four biomineralization genes of msi31, msi60, N16and N19. It was not significant for the difference of the expression levels among mantel of small individual and center or edge part of large individual mantle for the two genes of msi31and msi60, whereas a significant difference and highly significant difference was showed among these tissues for N19and N16respectively. N16was the unique gene that had a significant expression levels between center part and edge part of mantle tissue. Further analysis showed that there were highly significant differences for expression levels of msi31among center part and edge part of mantle for families of Cb, Cf, Ch and Cj. As for msi60, there were significant differences of expression levels among the two parts in families of Cb and Cf while there were highly significant differences of expression levels among two parts in another two families of Cj and Cp. Moreover, significant differences of expression level between center part and edge part of mantle tissue was identified just in one family of Cf for family of N19. Nevertheless, there was.no significant differences of expression levels of N16between the two parts of mantle for all eight tested families.There were highly significant corelationship for the expression between every two mineralization genes of msi31, msi60, N16and N19. There was no significant correlation between the expression of N16and growth traits, such’as the shell hight, shell length, twisted line length, shell width, and total weight, whereas there were significant or highly significant correlation between the expression levels and growth traits for the other genes of msi31, msi60and N19.In a conclusion, transcription of the mantle and pearl sac of P. fucata martensii were characterized, revealing dozens of genes involved in biomineralization and thousands of potential SNP loci or indels. Moreover, expression levels in mantle tissues were analyzed for four mineralization genes in eight families of P. fucata martensii, as well as the corelationships c:expression levels and growing traits. These results were helpful for both study of biomineralization mechanism, population genetics, functional genomics, and studies of molecular marker of P. fucata martensii. biomineralization and transcriptome of other pearl oyster.