Full-length Transcriptome Sequences and Identification of Putative Genes for Carotenoids Accumulation in Polymorphic Noble Scallop Chlamys Nobilis

Abstract Background: Carotenoids are ubiquitous in marine bivalves and the accumulation mechanism has attracted widespread interest, but still remains unclear. The enrichment carotenoids noble scallop Chlamys nobilis provide a model animal to explain the molecular mechanism of carotenoids in marine bivalves. For a better understanding of transcriptional data and putative genes involved in carotenoids accumulation in noble scallop, PacBio sequencing and RNA-seq data were jointed to analysis the differentially expressed genes in different tissues.Results: In the present study, we obtained 26,237 non-redundant transcripts, and total 9263 DEGs were identified among the five tissues, and 3361 were up-regulated and 4980 genes were down-regulated in golden scallop (rich in carotenoids). Examination of the GO terms indicated that the DEGs mainly related to metabolic process, binding, catalytic activity and cellular process. KEGG pathway analysis showed that DEGs mainly related to phagosome, protein processing in endoplasmic reticulum and lysosome. Carotenoids-related genes, including CD36, Retinoid X Receptor (RXR), glutathione S-transferase (GST) and low density lipoprotein (LDL) showed significantly difference between golden and brown scallops, and several genes function were also identified in the early developmental stages.Conclusions: This study revealed that there are large transcriptome differences between golden scallops and brown scallops, these results provide fundamental resources of large-scale full-length transcripts in C. nobilis and contribute to the understanding of carotenoids accumulation mechanism in mollusks.