Differential gene expression in the body wall of the sea cucumber (<italic>Apostichopus japonicus</italic>) under strong lighting and dark conditions.

Sea cucumber, <italic>Apostichopus japonicus</italic> is very sensitive to light changes. It is important to study the influence of light on the molecular response of <italic>A. japonicus</italic>. In this study, RNA-seq provided a general overview of the gene expression profiles of the body walls of <italic>A. japonicus</italic> exposed to strong light (“light”), normal light (“control”) and fully dark (“dark”) environment. In the comparisons of “control” vs. “dark”, ”control” vs. “light” and “dark” vs. “light”, 1 161, 113 and 1 705 differentially expressed genes (DEGs) were identified following the criteria of |log₂ratio|≥1 and FDR≤0.001, respectively. Gene ontology analysis showed that “cellular process” and “binding” enriched the most DEGs in the category of “biological process” and “molecular function”, while “cell” and “cell part” enriched the most DEGs in the category of “cellular component”. And the DEGs were mapped to 214, 41 and 229 pathways in the Kyoto Encyclopedia of Genes and Genomes database, and 51, 2 and 57 pathways were significantly enriched, respectively. Light-specific DEGs identified in this study will be important targets for further investigation to establish the biochemical mechanisms involved in the adaption of this sea cucumber to changes in the level of environmental light. [ABSTRACT FROM AUTHOR]