Identification and characterization of intestine microRNAs and targets in red swamp crayfish, Procambarus clarkii infected with white spot syndrome virus.

MicroRNAs (miRNAs) are small non-coding endogenous RNA molecules that play important roles in the innate immunity system of invertebrates, especially in the aspect of antivirus. In the present study, high-throughput small RNA Illumina sequencing systems were used to identify differentially expressed miRNAs (DEMs) from the intestines of Procambarus clarkii that were infected with white spot syndrome virus (WSSV). As a result, 39 known and 12 novel miRNAs were identified in both NG and WG small RNA libraries. Seven DEMs were determined to be involved in the antiviral innate immunity in the intestines of P. clarkii. The results of the target gene predictions of the DEMs showed that the putative target genes of these 7 DEMs are related to tight junctions, vascular smooth muscle contraction regulation of the actin cytoskeleton, focal adhesion, RNA transport, mRNA surveillance, viral carcinogenesis, and Salmonella infection. These results provide theoretical insights for future studies on the antiviral immunity of crustaceans.