RNA-Seq Analysis Revealed the Virulence Regulatory Network Mediated by the Ferric Uptake Regulator (Fur) in <i>Apostichopus japonicus</i> Pathogenesis Induced by <i>Vibrio splendidus</i>
The uptake and utilization of iron by bacteria must be strictly controlled. The ferric uptake regulator (Fur) is a global transcription factor widely present in bacteria that can perceive cellular iron levels and adjust the expressions of various genes accordingly. Our earlier research demonstrated...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-05-01
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| Series: | Microorganisms |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-2607/13/6/1173 |
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| Summary: | The uptake and utilization of iron by bacteria must be strictly controlled. The ferric uptake regulator (Fur) is a global transcription factor widely present in bacteria that can perceive cellular iron levels and adjust the expressions of various genes accordingly. Our earlier research demonstrated that the knockdown of the <i>fur</i> gene in <i>Vibrio splendidus</i> significantly reduced its lethality to <i>Apostichopus japonicus</i>. Although the functions and mechanisms of Fur in regulating bacterial virulence genes have been extensively studied, its virulence regulatory network during <i>V. splendidus</i> pathogenesis in <i>A. japonicus</i> remains unclear. In this article, transcriptome sequencing analysis of <i>V. splendidus</i> under different iron conditions reveals substantial differential gene expressions in the simulated pathogenic environments, identifying 1185 differentially expressed genes, including 198 downregulated and 987 upregulated genes. Comparative analysis between wild-type and <i>Vsfur</i> knockdown strains shows that <i>Vsfur</i> knockdown altered the expression of 3593 genes in <i>V. splendidus</i>, with the most significant differential expression observed under simulated pathogenic conditions (1030 upregulated and 72 downregulated). KEGG enrichment analysis indicates that <i>Vsfur</i> knockdown caused significant gene enrichment in the flagellar assembly pathway and bacterial secretion system, critically impairing flagellar synthesis and secretion system function in <i>V. splendidus</i>. Eight genes selected for qRT-PCR validation showed expression levels in line with the RNA-seq results. Consistent with the transcriptomic results, <i>Vsfur</i> knockdown resulted in reduced antioxidant capacity, bacterial competitiveness, and cytotoxicity in <i>V. splendidus</i>. These findings elucidate the virulence regulatory mechanism of Fur in <i>V. splendidus</i> and provide a reference for understanding the occurrence of <i>A. japonicus</i> skin ulcer syndrome. |
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| ISSN: | 2076-2607 |