Transcriptomic responses to RGNNV and Vibrio alginolyticus infection in the spleen of hybrid grouper ( Epinephelus lanceolatus♂ x Epinephelus fuscoguttatus♀)

The hybrid grouper ( Epinephelus lanceolatus male male x E. fuscoguttatus female) female) is a novel and commercially important fish for mariculture in China. Recent years, the outbreak of viral and bacterial diseases have caused huge losses of hybrid grouper culture. However, the immune response of hybrid grouper against viral and bacterial infection remains unexplored. In this study, a total of 9 splenic transcriptomic libraries of hybrid grouper including untreated control, Red-spotted grouper nervous necrosis virus (RGNNV)-challenged, Vibrio alginolyticus-challenged-challenged were constructed. A sum of 6024 differentially expressed genes (DEGs) with significant differences were identified, of which the overlapped DEGs between RGNNV and V. alginolyticus challenged were significantly enriched in multiple immune-related pathway including interleukin-17 NOD-like receptor, C-type lectin receptor, chemokine signaling pathway and natural killer cell mediated cytotoxicity, indicating their important roles in immune defense of hybrid grouper against (both) viral and bacterial infection. To the best of our knowledge, this is the first report that investigated the immune response of hybrid grouper following viral and bacterial pathogen stimuli using transcriptomic analysis. These results provide comprehensive understandings of the innate immunity of hybrid grouper and valuable references to develop disease control strategy in grouper aquaculture.