丁香酚对青枯雷尔氏菌的抑菌效果及作用机制

The antibacterial effect and action mechanism of eugenol on bacterial wilt pathogen Ralstonia solanacearum

中文关键词:丁香酚  青枯雷尔氏菌  青枯病  转录组

keywords:eugenol  Ralstonia solanacearum  bacterial wilt  transcriptome

中文摘要:为探究丁香酚对青枯病致病菌的抑菌活性和作用机制，以青枯雷尔氏菌Ralstonia solanacearum为研究对象，采用微量二倍稀释法、琼脂扩散法、毛细管法和结晶紫染色法等方法测定丁香酚对青枯雷尔氏菌最小抑菌浓度（minimal inhibitory concentration，MIC）、最低杀菌浓度（mini‐mum bactericidal concentration，MBC）、运动性、趋化性和生物被膜的影响；对丁香酚处理与否的青枯雷尔氏菌进行转录组分析，并使用实时荧光定量PCR（real-time quantitative PCR，RT-qPCR）技术对几个关键基因表达量进行测定。结果表明：丁香酚对青枯雷尔氏菌的MIC为125 μg/mL，MBC为500 μg/mL。当丁香酚浓度大于62.5 μg/mL时，能著抑制青枯雷尔氏菌的生长、运动性和生物被膜的形成；当丁香酚浓度大于125 μg/mL时，能显著促进青枯雷尔氏菌的趋避性。转录组分析结果显示，丁香酚处理的青枯雷尔氏菌中有174个差异表达基因（differentially expressed gene，DEG）上调，347个DEG下调；GO分析结果表明DEG主要富集在前体代谢物与能量的生成、非膜结合的细胞器和RNA结合等生物学过程中；KEGG分析表明DEG主要富集在碳代谢、氧化磷酸化和核糖体等信号通路中。

Abstract:To investigate the antibacterial activity and action mechanism of eugenol against the pathogens causing bacterial wilt, Ralstonia solanacearum was used as the target bacterium. Approaches such as the microdilution method, agar diffusion assay, capillary assay, and crystal violet staining were employed to determine the minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC), motility, chemotaxis, and biofilm formation of R. solanacearum under treatment with eugenol. Transcriptome analysis was performed on R. solanacearum with and without eugenol treatment, and the expression levels of several key genes were measured using real-time quantitative PCR (RT-qPCR). The results showed that the MIC of eugenol against R. solanacearum was 125 μg/mL, and the MBC was 500 μg/mL. When the concentration of eugenol exceeded 62.5 μg/mL, it significantly inhibited the growth, motility, and biofilm formation of R. solanacearum. At concentrations above 125 μg/mL, eugenol significantly promoted the repellent behavior of R. solanacearum. Transcriptome analysis revealed 174 upregulated differentially expressed genes (DEGs) and 347 downregulated DEGs in eugenol-treated R. solanacearum. Gene ontology (GO) analysis indicated that the DEGs were primarily enriched in metabolic processes such as generation of precursor metabolites and energy, non-membrane-bound organelle, and RNA binding. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis showed that the DEGs were mainly enriched in pathways such as carbon metabolism, oxidative phosphorylation, and ribosome.