Burns Justin L, Jariwala Parth B, Rivera Shannon, Fontaine Benjamin M, Briggs Laura, Weinert Emily E
Department of Chemistry, Emory University , 1515 Dickey Drive, Atlanta, Georgia 30322, United States.
ACS Chem Biol. 2017 Aug 18;12(8):2070-2077. doi: 10.1021/acschembio.7b00380. Epub 2017 Jun 28.
Bacterial pathogens utilize numerous signals to identify the presence of their host and coordinate changes in gene expression that allow for infection. Within plant pathogens, these signals typically include small molecules and/or proteins from their plant hosts and bacterial quorum sensing molecules to ensure sufficient bacterial cell density for successful infection. In addition, bacteria use environmental signals to identify conditions when the host defenses are weakened and potentially to signal entry into an appropriate host/niche for infection. A globin coupled sensor protein (GCS), termed PccGCS, within the soft rot bacterium Pectobacterium carotovorum ssp. carotovorum WPP14 has been identified as an O sensor and demonstrated to alter virulence factor excretion and control motility, with deletion of PccGCS resulting in decreased rotting of a potato host. Using small molecules that modulate bacterial growth and quorum sensing, PccGCS signaling also has been shown to modulate quorum sensing pathways, resulting in the PccGCS deletion strain being more sensitive to plant-derived phenolic acids, which can function as quorum sensing inhibitors, and exhibiting increased N-acylhomoserine lactone (AHL) production. These findings highlight a role for GCS proteins in controlling key O-dependent phenotypes of pathogenic bacteria and suggest that modulating GCS signaling to limit P. carotovorum motility may provide a means to decrease rotting of plant hosts.
细菌病原体利用多种信号来识别宿主的存在，并协调基因表达的变化以实现感染。在植物病原体中，这些信号通常包括来自植物宿主的小分子和/或蛋白质以及细菌群体感应分子，以确保有足够的细菌细胞密度来成功感染。此外，细菌利用环境信号来识别宿主防御减弱的情况，并可能以此为信号进入合适的宿主/生态位进行感染。在软腐病菌胡萝卜软腐果胶杆菌胡萝卜软腐亚种WPP14中，一种名为PccGCS的球蛋白偶联传感器蛋白已被鉴定为氧气传感器，并被证明会改变毒力因子的分泌并控制运动性，缺失PccGCS会导致马铃薯宿主的腐烂减少。利用调节细菌生长和群体感应的小分子，PccGCS信号传导也已被证明可调节群体感应途径，导致PccGCS缺失菌株对可作为群体感应抑制剂的植物源酚酸更敏感，并表现出N-酰基高丝氨酸内酯（AHL）产量增加。这些发现突出了GCS蛋白在控制病原菌关键氧依赖性表型中的作用，并表明调节GCS信号传导以限制胡萝卜软腐果胶杆菌的运动性可能提供一种减少植物宿主腐烂的方法。
