Abstract

The largemouth bass ( Micropterus salmoides ), commonly known as the California bass, is a species of significant economic importance in global freshwater aquaculture. Largemouth bass virus (LMBV) has emerged as a major pathogen that poses a substantial threat to the sustainability of largemouth bass aquaculture. In this study, we established a novel Micropterus salmoides caudal fin (MSCF) cell line that supports LMBV propagation and enables investigation of virus-induced fundamental patterns of molecular responses. Characterization of the MSCF line revealed an initial mixture of epithelial-like and fibroblast-like cells that became uniformly epithelial by passage 20. Transcriptomic analysis revealed that LMBV infection significantly altered the transcription levels of 262 genes (201 up-regulated genes and 61 down-regulated), which were functionally enriched in key antiviral pathways such as apoptosis, FoxO signaling, and RIG-I-like receptor signaling. The observed expression patterns suggest that LMBV employs a potential strategy to manipulate host cell survival and disrupt innate immune responses. Collectively, we have developed an LMBV-susceptible cell line (MSCF), which provides an ideal platform for studying LMBV virology and elucidating the host defense mechanisms against LMBV.