Comparative Transcriptome Analysis of the Gills from the Chinese Mitten Crab (Eriocheir japonica sinensis) Exposed to the Heavy Metal Cadmium

Abstract

Heavy metal Cadmium (Cd) pollution has become a potential environmental problem, and it threatens aquatic organisms including economic crabs and shrimps. Chinese mitten crab is a native species in East Asia, and it is the most important economic crab species in China. However, there are only a few studies about gills responding to Cd stress in the Chinese mitten crab at a molecular level. To gain better understanding of the oxidative stress system (antioxidant defense) of the E. j. sinensis, in this study, RNA-Seq was applied to obtain gene expression profile from the mitten crab's gills in response to Cd for 24h, and yielding 39,612,948 high-quality clean reads from which 570,847 transcripts and 504,889 unigenes are assembled by removing redundancy and transcripts with low coverage. A total of 1544 differential expression genes (DGEs) are identified. GO functional analysis and KEGG pathway analysis indicated some vital pathways and genes in response to the challenge. Four genes related to immune response and detoxification are selected to validate the DGE results by qRT-PCR. This comparative transcriptome provides valuable molecular information about on the mechanisms of the Chinese mitten crab responding to Cd that lays the foundation for further understanding of heavy metals stress.