Transcriptome analysis reveals the DNA replication genes response to Vibrio anguillarum and NNV infection in Jinhu grouper (Epinephelus fuscoguttatus♀ × Epinephelus tukulal♂)

Vibrio anguillarum acts as an infectious agent in the aquaculture industry that causes a fatal hemolytic septicaemic disease in fish and shellfish. Viral nervous necrosis (VNN) disease seriously impacts the healthy development of the aquaculture industry. While the detrimental effects of V. anguillarum and NNV have been widely researched on freshwater and marine fish, whether they affect DNA replication in fish is unclear. In this study, we used Jinhu grouper as a model to investigate the influence of V. anguillarum and NNV on their DNA replication. By RNA-seq analysis in conjunction with gene set enrichment analysis, we found a significant upregulation of genes related to DNA replication in the liver and spleen of the Jinhu grouper after V. anguillarum infection while a prominent downregulation of genes related to DNA replication in the brain of the Jinhu grouper after NNV infection. We identified 27, 29 and 18 key genes involved in DNA replication that may respond to V. anguillarum and NNV infection and selected and identified six DNA replication genes (pole, pole2, pold1, pola1, pcna and mcm2). In addition, our results indicated that these genes exhibit tissue-specific expression patterns, with an increasing pattern of expression when V. anguillarum infected and a decreasing pattern when NNV infected. These results may provide valuable understanding on the underlying mechanisms of V. anguillarum and NNV infection in fish.