Identification of genes directly regulated by LvBlimp1 in shrimp macrophage-like phagocytes.

Litopenaeus vannamei B lymphocyte-induced maturation protein 1 (LvBlimp1) is a transcription factor expressed in macrophage-like phagocytes that modulates immune responses via direct bactericidal activity, opsonization, and phagocytosis. However, the molecular targets and regulatory architecture by which LvBlimp1 controls shrimp disease resistance remain poorly defined. In this study, ChIP-seq was performed in shrimp hemocytes to identify genome-wide binding targets of LvBlimp1. Five core downstream genes (MAP1B, SLC46, TACC1, COL3A1, and LGMN) are directly regulated by LvBlimp1 were identified through integrative analysis of ChIP-seq data, transcriptomes following LvBlimp1 knockdown, and marker gene sets of macrophage-like phagocytes. Four targets (MAP1B, SLC46, TACC1, COL3A1) were verified as direct transcriptional targets after FIMO analysis and ChIP-qPCR. Distinct expression patterns and regulatory correlations were observed in public transcriptomic datasets under white spot syndrome virus (WSSV) infection, Vibrio alginolyticus (V. alginolyticus) infection, and low-salinity stress, indicating that stress-specific immune responses are orchestrated by LvBlimp1 selective target engagement. Significantly altered expression of LvBlimp1 and its targets was detected in Vibrio parahaemolyticus-resistant and WSSV-resistant shrimp families, with divergent expression profiles observed under distinct pathogenic challenges. This study constructs a context-dependent transcriptional regulatory network of LvBlimp1 in shrimp innate immunity. Identify MAP1B and SLC46 as candidates for dissecting antimicrobial immune mechanisms against WSSV and V. alginolyticus, and highlight LvBlimp1, COL3A1, and TACC1 as high-value targets for potential immune regulation of shrimp with improved low-salinity tolerance and pathogen resistance. These results provide mechanistic insights into stimulus-specific immune responses in crustaceans and promising LvBlimp1 direct target genes associated with immune response of disease-resistant shrimp.