Establishment of an ovarian cell line from tomato grouper (Cephalopholis sonnerati) and its transcriptome response to ISKNV infection.

Tomato grouper (Cephalopholis sonnerati) is an economically efficient and nutritious species, whose expansion through factory farming in recent years has been hindered by the frequent occurrence of diseases, limiting the development of its aquaculture industry. The establishment of reliable cell lines is fundamental for conducting comprehensive immunological and virological research on the tomato grouper. In this study, we established an ovarian cell line from tomato grouper, designated TGGO. The TGGO cells were passaged for over 70 passages and cultured in L-15 medium supplemented with 15 % FBS at 27 °C, exhibiting a fibroblast-like morphology. It was determined that the TGGO cells were derived from the tomato grouper through mitochondrial coI gene sequencing. Karyotype analysis determined a chromosome number of 2n = 48. The survival rate of cells cryopreserved in liquid nitrogen for 5 months exceeded 70 % upon thawing. The cells were transfected with the EGFP-N3 plasmid and Cy3-labeled scrambled siRNA, and clear green and red fluorescence were observed. Additionally, the cells exhibited sensitivity to ISKNV, displaying a clear cytopathic effect (CPE) at 24 h post-infection, with viral particles observed under transmission electron microscopy. Transcriptomic analysis of ISKNV-infected TGGO cells showed significant enrichment of differentially expressed genes in pathways related to viral infection, nucleic acid replication, and immune response. Notable pathways include ECM-receptor interaction, PI3K-Akt signaling, viral protein interaction with cytokines and cytokine receptors, ribosome biogenesis, and DNA replication. These findings suggest that the TGGO cell line is susceptible to ISKNV infection and can be used to study this virus. Therefore, the TGGO cell line is anticipated to become a valuable resource for in vitro research on virology and other biological processes in tomato grouper.