Profiling and comparison of color body wall transcriptome of normal juvenile sea cucumber (Apostichopus japonicus) and those produced by crossing albino

Sea cucumber (Apostichopus japonicus) is one of the most important aquaculture animals in China. Usually its normal body color is black that fits its living environment. The juvenile individuals obtained by crossing albino sea cucumber segregated in body color. To document the transcriptome difference between albino associating sea cucumber and the control, we sequenced their transcriptomes with RNA-seq. Approximately, 4.790 million (M) and 4.884 M reads, 200 nt in length, were generated from the body wall of albino associating sea cucumber and the control, respectively, from them, 9550 (46.81%) putative genes were identified. In total, 583 genes were found to express differentially between albino associating sea cucumber and the control. Of these differentially expressed genes (DEGs), 4.8% changed more than five-folds. The expression levels of eight DEGs were confirmed with real-time PCR. The changing trend of these DEGs detected with real-time PCR agreed well with that detected with RNA-seq, although the change degree of some DEGs was different. Four significantly enriched pathways were identified for DEGs, which included phagocytosis, Staphylococcus aureus infection, ECM-receptor interaction and focal adhesion. These pathways were helpful for understanding the physiological difference between albino associating sea cucumber and the control.