为探究黄芩苷抑制嗜水气单胞菌生长的作用机制。通过分析黄芩苷对嗜水气单胞菌(Aeromonas hydrophila)生长、菌体形态的影响及作用后的转录组数据，挖掘其抑制该菌的关键候选基因。实验具体如下：采用倍比稀释法测定黄芩苷对嗜水气单胞菌的最小抑菌浓度(Minimum inhibitory concentration, MIC)与最小杀菌浓度(Minimum bactericidal concentration, MBC);将该菌接种于含不同浓度黄芩苷的液体培养基，测定OD₆₀₀值以绘制生长曲线，通过透射电镜观察菌体形态变化；收集菌体提取RNA进行高通量转录组测序，以|log₂(Fold change)|≥1且P≤0.05为阈值筛选差异基因，经GO注释与KEGG功能富集分析筛选关键基因；通过体内外实验验证转录组测序结果。研究表明，黄芩苷对嗜水气单胞菌的MIC和MBC均为7.81 mg/mL。1/2 MIC浓度黄芩苷延长了细菌进入稳定期的时间，并对细菌生长有一定抑制效果；1 MIC浓度黄芩苷显著抑制了嗜水气单胞菌生长。透射电镜观察显示，黄芩苷处理后菌体表面不光滑，细胞壁边缘粗糙，细菌的正常结构被破坏，表明黄芩苷能够破坏嗜水气单胞菌结构的完整性。转录组测序结果显示，在黄芩苷作用于细菌后，共有908个基因呈现出不同程度的差异表达，其中，556个基因表达上调，352个基因表达下调，差异表达基因显著富集于嗜水气单胞菌的双组分系统、磷酸转移酶系统和氨基酸合成代谢相关编码基因。GO功能分析发现，差异基因参与细胞组分、胞外区域以及催化活性等过程；KEGG富集分析表明，差异基因主要富集在蛋白质合成、遗传信息处理以及支链氨基酸的生物合成等相关途径。RT-qPCR实验结果表明，转录组数据准确性高。动物试验显示，黄芩苷不仅能提升抗氧化能力，还可显著调控脾脏IFN-γ、TNF-α等炎症相关基因的表达，有效改善机体氧化应激与炎症状态。研究结果显示，黄芩苷能够显著抑制嗜水气单胞菌生长，破坏菌体结构完整性，通过影响胞外运输代谢、双组分系统以及相关氨基酸生物合成与代谢等信号通路，改变嗜水气单胞菌的生理生化功能和毒力。

To explore the mechanism of action of baicalin in inhibiting the growth of Aeromonas hydrophila. By analyzing the effects of baicalin on the growth, morphology, and transcriptome data of A. hydrophila, key candidate genes for its inhibition were identified. Specifically, the minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) of baicalin against A. hydrophila were determined using the serial dilution method. The bacteria were inoculated into liquid media containing different concentrations of baicalin, and the OD₆₀₀ values were measured to construct growth curves. The morphological changes of the bacteria were observed using transmission electron microscopy. RNA was extracted from the collected bacteria for high-throughput transcriptome sequencing. Differential genes were screened using the threshold of |log₂(Fold change)|≥1 and P≤0.05, and key genes were identified through GO annotation and KEGG functional enrichment analysis. The transcriptome sequencing results were verified using RT-qPCR. The MIC and MBC of baicalin against A. hydrophila were both 7.81 mg/mL. Baicalin at a concentration of 1/2 MIC prolonged the time for the bacteria to enter the stationary phase and had a certain inhibitory effect on bacterial growth. Baicalin at a concentration of 1 MIC significantly inhibited the growth of A. hydrophila. Transmission electron microscopy revealed that the surface of the bacteria treated with baicalin was not smooth, the edges of the cell wall were rough, and the normal structure of the bacteria was destroyed, indicating that baicalin could disrupt the structural integrity of A. hydrophila. The transcriptome sequencing results showed that after baicalin acted on the bacteria, a total of 908 genes exhibited differential expression to varying degrees, among which 556 genes were upregulated and 352 genes were downregulated. The differentially expressed genes were significantly enriched in the two-component system, phosphotransferase system, and amino acid synthesis and metabolism-related coding genes of A. hydrophila. GO functional analysis revealed that the differentially expressed genes were involved in processes such as cellular composition, extracellular region, and catalytic activity. KEGG enrichment analysis indicated that the differentially expressed genes were mainly enriched in pathways related to protein synthesis, genetic information processing, and the biosynthesis of branched-chain amino acids. The results of the RT-qPCR experiment demonstrated the high accuracy of the transcriptome data. Animal experiments showed that baicalin not only enhanced antioxidant capacity but also significantly regulated the expression of inflammation-related genes such as spleen IFN-γ and TNF-α, effectively improving oxidative stress and inflammatory states in the body. Baicalin can significantly inhibit the growth of A. hydrophila, disrupt the structural integrity of the bacterial cell, and alter the physiological and biochemical functions and virulence of A. hydrophila by affecting extracellular transport metabolism, two-component systems, and related amino acid synthesis and metabolism signaling pathways. Furthermore, it can alleviate oxidative stress and inflammatory responses in infected animals.