Dynamics of MiRNA Transcriptome in Turbot (Scophthalmus maximus L.) Intestine Following Vibrio anguillarum Infection.

MicroRNAs (miRNAs) are a group of small non-coding RNAs, which could bind to the 3'-untranslated regions of their target mRNAs to regulate gene expression in various biological processes, including immune-regulated signaling pathways. Turbot (Scophthalmus maximus L.), an important commercial fish species in China, has been suffering with Vibrio anguillarum infection resulted in dramatic economic loss. Therefore, we investigated the expression profiles of miRNAs, as well as the immune-related miRNA-mRNA pairs in turbot intestine at 1 h, 4 h, and 12 h following V. anguillarum infection. As a result, 266 predicted novel miRNAs and 283 conserved miRNAs belonging to 92 miRNA families were detected. A total of 44 miRNAs were differentially expressed in the intestine following V. anguillarum infection. Following prediction, the potential target genes of differentially expressed miRNAs were grouped into a wide range of functional categories, including immune defense/evasion, inflammatory responses, RIG-I signaling pathway, and Toll-like receptor signaling pathway. Moreover, we selected 15 differentially expressed immune genes and their related differentially expressed miRNAs to construct an interaction network for V. anguillarum infection in turbot. These results suggested that in teleost, as in higher vertebrates, miRNAs prominently contribute to immune responses, protecting the host against infection. In addition, this is the first report of comprehensive identification of turbot miRNAs being differentially regulated in the intestine related to V. anguillarum infection. Our results provided an opportunity for further understanding of the molecular mechanisms of miRNA regulation in turbot host-pathogen interactions.