School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China.
School of Chinese Ethnic Medicine, Guizhou Minzu University, Guizhou City, Guiyang Province 550025, China.
Int J Food Microbiol. 2025 Jan 2;426:110916. doi: 10.1016/j.ijfoodmicro.2024.110916. Epub 2024 Sep 13.
The quorum-sensing receptor SdiA is vital for regulating the desiccation tolerance of C. sakazakii, yet the specific mechanism remains elusive. Herein, transcriptomics and phenotypic analysis were employed to explore the response of C. sakazakii wild type (WT) and sdiA knockout strain (ΔsdiA) under drying conditions. Following 20 days of drying in powdered infant formula (PIF), WT exhibited 4 log CFU/g higher survival rates compared to ΔsdiA. Transcriptome revealed similar expression patterns between csrA and sdiA, their interaction was confirmed both by protein-protein interaction analysis and yeast two-hybrid assays. Notably, genes associated with flagellar assembly and chemotaxis (flg, fli, che, mot regulon) showed significantly higher expression levels in WT than in ΔsdiA, indicating a reduced capacity for flagellar synthesis in ΔsdiA, which was consistent with cellular morphology observations. Similarly, genes involved in trehalose biosynthesis (ostAB, treYZS) and uptake (thuEFGK) exhibited similar expression patterns to sdiA, with higher levels of trehalose accumulation observed in WT under desiccation conditions compared to ΔsdiA. Furthermore, WT demonstrated enhanced protein and DNA synthesis capabilities under desiccation stress. Higher expression levels of genes related to oxidative phosphorylation were also noted in WT, ensuring efficient cellular ATP synthesis. This study offers valuable insights into how SdiA influences the desiccation tolerance of C. sakazakii, paving the way for targeted strategies to inhibit and control this bacterium.
群体感应受体 SdiA 对调控阪崎克罗诺杆菌的干燥耐受性至关重要，但具体机制仍不清楚。本研究采用转录组学和表型分析方法，探究了干燥条件下阪崎克罗诺杆菌野生型（WT）和 sdiA 敲除菌株（ΔsdiA）的响应。在粉状婴儿配方食品（PIF）中干燥 20 天后，WT 的存活数比 ΔsdiA 高 4 个对数 CFU/g。转录组学揭示了 csrA 和 sdiA 的表达模式相似，通过蛋白质-蛋白质相互作用分析和酵母双杂交实验证实了它们之间的相互作用。值得注意的是，与鞭毛组装和趋化性相关的基因（flg、fli、che、mot 调控子）在 WT 中的表达水平明显高于 ΔsdiA，表明 ΔsdiA 中鞭毛合成能力降低，这与细胞形态观察结果一致。同样，参与海藻糖生物合成（ostAB、treYZS）和摄取（thuEFGK）的基因与 sdiA 表现出相似的表达模式，在干燥条件下 WT 中观察到的海藻糖积累水平高于 ΔsdiA。此外，WT 在干燥胁迫下表现出增强的蛋白质和 DNA 合成能力。WT 中还观察到与氧化磷酸化相关的基因表达水平更高，确保了有效的细胞 ATP 合成。本研究深入了解了 SdiA 如何影响阪崎克罗诺杆菌的干燥耐受性，为靶向抑制和控制该细菌提供了重要线索。
