Fig. 1 Analysis of quantitative proteomics data A: Growth curves of A. hydrophila under different concentrations of enrofloxacin stress. B: SDS-PAGE profiles of A. hydrophila with or without enrofloxacin treatment. C: Correlation analysis of protein expression of three biological replicates in each group was carried out by correlation coefficient. D: Volcanic plots showing the abundance of differential protein expression. The blue dots represent the differentially downregulated proteins, the orange dots represent the differentially up-regulated proteins, and the gray dots represent the non-differentially expressed proteins

Fig. 2 GO and KEGG enrichment analysis of differentially expressed proteins under ENR stress A: Using DAVID online website and R language to analyze the biological processes of differentially expressed proteins. B: Molecular function. C: Enrichment analysis of KEGG metabolic pathway

Fig. 3 Protein-protein interaction prediction（PPI）net-work of differential proteins under ENR stress The extended network of hub proteins. Different colors indicate the fold change of different proteins（Log2）

Fig. 4 Growths of WT and sulfur metabolism-related gene deletion strains supplemented with 2 mmol/L cysteine and ENR in sulfur limiting medium, respectively A: 2 mmol/L cysteine was added to the sulfur-limited medium. B: Sulfur-limited medium. C: Sulfur limited medium with 2 mmol/L cysteine and 0.78 µg/mL ENR. D: ENR was added to the sulfur-limited medium

Fig. 5 qPCR validation of proteomic data qPCR was used to verify the mRNA expression levels of 8 sulfur metabolism related genes in A. hydrophila under ENR stress or not