Integrative transcriptomic and proteomic analyses of pathogenic Aeromonas hydrophila in response to stress hormone norepinephrine

摘要

Abstract Stress is commonly considered as a significant contributing factor in fish disease, and stress hormones could directly influence the pathogenicity of bacteria. To identify the mechanism of Aeromonas hydrophila that responds to norepinephrine (NE), we integrated transcriptomic and proteomic analyses of A. hydrophila grown in serum‐SAPI medium with or without NE using RNA Sequencing (RNA‐seq) and isobaric tags for relative and absolute quantification (iTRAQ) analyses. There were 406 differentially expression genes (296 upregulated and 110 downregulated) and 62 differentially expression proteins (31 upregulated and 31 downregulated). The integrative analyses showed that 14 genes displayed consistent expression at both transcript and protein levels, while 7 genes exhibited contrasting expression. Validation with real‐time quantitative PCR showed that the expression of four selected DEGs was consistent with the pattern of transcriptome profile. Further analyses revealed that the expression of virulence factor transcripts was significantly increased, including haemolysin and structural toxin protein RtxA. Furthermore, the transcripts and proteins involved in iron metabolism were also changed. The expression of bacterioferritin and iron‐containing proteins was enhanced at transcript level; conversely, the genes involved in amonabactin synthesis and transport were repressed at both transcript and protein levels. Notably, novel observations revealed that the gene expression of type 6 secretion system (T6SS) and pilus‐related loci was inhibited in A. hydrophila after exposure to NE. These results corroborate previous findings that NE can not only improve the growth and virulence of A. hydrophila, but also provide a new suggestion about the T6SS role in bacterial cell–cell interaction for further research.