De novo transcriptome sequencing and analysis of Rapana venosa from six different developmental stages using Hi-seq 2500.

The carnivorous whelk Rapana venosa is regarded as a biological invader with strong ecological fitness in the United States, Argentina, France and other countries. R. venosa may seriously damage bivalve resources. Nonetheless, in China, R. venosa is an important commercial species. Larval development, especially metamorphosis, influences the natural population and industrial breeding. However, there are few studies on the early development of R. venosa, and our understanding is further limited by a lack of genomic information. In this study, de novo sequencing was performed to obtain a comprehensive transcriptome profile during early development. A Hi-seq 2500 sequencing run produced 148,737,902 raw reads that were assembled into 1,137,556 unigenes (average length of 619 nucleotides, of which 49,673 could be annotated). The unigenes were assigned to biological processes and functions after annotation in Gene Ontology, eukaryotic Ortholog Groups and Kyoto Encyclopedia of Genes and Genomes. We also identified 93,196 simple sequence repeats among the unigenes. Six unique sequences associated with neuroendocrine function were analyzed by quantitative real-time PCR. Our data represent the first comprehensive transcriptomic resource for R. venosa. Functional annotation of the unigenes involved in various biological processes could stimulate research on the mechanisms of early development in this species. Understanding the mechanism of early development and metamorphosis would benefit antifouling research and aquaculture of R. venosa.