Yan Congyang, Li Xue, Zhang Gongliang, Zhu Yaolei, Bi Jingran, Hao Hongshun, Hou Hongman
School of Food Science and Technology, Dalian Polytechnic University, Dalian, China.
Liaoning Key Lab for Aquatic Processing Quality and Safety, Dalian, China.
Front Microbiol. 2021 Mar 2;12:567942. doi: 10.3389/fmicb.2021.567942. eCollection 2021.
Quorum sensing (QS) is a widespread regulatory mechanism in bacteria used to coordinate target gene expression with cell density. Thus far, little is known about the regulatory relationship between QS and cell density in terms of metabolic pathways in H4. In this study, transcriptomics analysis was performed under two conditions to address this question. The comparative transcriptome of H4 wild-type at high cell density (OD = 1.7) relative to low cell density (OD = 0.3) was considered as growth phase-dependent manner (GPDM), and the transcriptome profile of deletion mutant (Δ) compared to the wild-type was considered as QS-mediated regulation. In all, we identified 206 differentially expressed genes (DEGs) mainly presented in chemotaxis, TCA cycle, two-component system, ABC transporters and pyruvate metabolism, co-regulated by the both density-dependent regulation, and the results were validated by qPCR and swimming phenotypic assays. Aside from the co-regulated DEGs, we also found that 59 DEGs, mediated by density-independent QS, function in pentose phosphate and histidine metabolism and that 2084 cell-density-dependent DEGs involved in glycolysis/gluconeogenesis and phenylalanine metabolism were influenced only by GPDM from significantly enriched analysis of transcriptome data. The findings provided new information about the interplay between two density-dependent metabolic regulation, which could assist with the formulation of control strategies for this opportunistic pathogen, especially at high cell density.
群体感应（QS）是细菌中一种广泛存在的调控机制，用于将靶基因表达与细胞密度协调起来。到目前为止，关于H4中群体感应与细胞密度在代谢途径方面的调控关系，我们了解得还很少。在本研究中，我们在两种条件下进行了转录组学分析以解决这个问题。将H4野生型在高细胞密度（OD = 1.7）相对于低细胞密度（OD = 0.3）下的比较转录组视为生长阶段依赖性方式（GPDM），将缺失突变体（Δ）与野生型相比的转录组图谱视为群体感应介导的调控。总体而言，我们鉴定出206个差异表达基因（DEGs），主要存在于趋化作用、三羧酸循环、双组分系统、ABC转运蛋白和丙酮酸代谢中，由密度依赖性调控共同调节，并且结果通过定量PCR和游动表型分析得到验证。除了共同调节的DEGs外，我们还发现59个由非密度依赖性群体感应介导的DEGs在磷酸戊糖和组氨酸代谢中起作用，并且从转录组数据的显著富集分析中发现，2084个参与糖酵解/糖异生和苯丙氨酸代谢的细胞密度依赖性DEGs仅受GPDM影响。这些发现提供了关于两种密度依赖性代谢调控之间相互作用的新信息，这有助于制定针对这种机会致病菌的控制策略，特别是在高细胞密度时。
