Glucose Level Affects the Regulation of MgaSpn on Virulence and Adaptability of Streptococcus pneumoniae

Streptococcus pneumoniae can regulate virulence gene expression by sensing environmental changes, which is the key to pathogenicity. Carbohydrate is a significant environmental factor affecting the growth and virulence of bacteria. Here, we found that glucose level could affect the content of phosphocholine, which was mediated by MgaSpn. MgaSpn belongs to a virulence regulator (PCVR) family containing phosphotransferase system (PTS) regulatory domains (PRDs). PTS can phosphorylate MgaSpn to varying degrees according to the availability of glucose, thereby altering its virulence regulation. In addition, Transcriptome analysis of wild-type D39s between low and high sugar concentrations revealed that MgaSpn was also involved in the regulation of carbon metabolism inhibition (CCR) and translation process, which made S.pneumoniae still have strong competitiveness in fluctuating environments. In contrast, MgaSpn is closely related to virulence, carbohydrate metabolism, and environmental adaptability of Streptococcus pneumoniae.

肺炎链球菌（Streptococcus pneumoniae）可通过感知环境变化调控毒力基因表达，这是其致病的核心关键。碳水化合物是影响细菌生长与毒力的重要环境因子。本研究发现，葡萄糖水平可影响磷酸胆碱（phosphocholine）的含量，该过程由MgaSpn介导。MgaSpn属于一类携带有磷酸转移酶系统（PTS）调控结构域（PRDs）的毒力调控因子（PCVR）家族。磷酸转移酶系统可根据葡萄糖的可利用程度，对MgaSpn进行不同程度的磷酸化修饰，进而改变其毒力调控活性。此外，对野生型D39s在高、低糖浓度下的转录组分析显示，MgaSpn还参与了碳代谢物阻遏（CCR）与翻译过程的调控，这使得肺炎链球菌在波动环境中仍具备较强的竞争优势。综上，MgaSpn与肺炎链球菌的毒力、碳水化合物代谢及环境适应性密切相关。