Establishment of a caudal fin cell line from largemouth bass (Micropterus salmoides) and its transcriptomic response to largemouth bass virus infection.

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.