CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
University of Chinese Academy of Sciences, Beijing, China.
Appl Environ Microbiol. 2018 Jul 2;84(14). doi: 10.1128/AEM.00865-18. Print 2018 Jul 15.
is a valuable model organism due to its versatile respiration capability and bioenergetic flexibility, both of which are critical to its survival in different environments. Quorum sensing (QS) plays a crucial role in the regulation of many cell functions; however, whether QS systems play a role in is unknown. In this study, we demonstrated that iron uptake systems in were directly regulated by a newly identified QS system. Genes coding for TonB-dependent systems, which transport chelated iron, were transcribed at higher levels in the QS-defective mutants. In contrast, genes coding for the Fbp system, which is TonB independent and transports unchelated ferric iron, were downregulated in the mutants. In brief, QS in triggers a switch in iron uptake from TonB-dependent to TonB-independent transport during biofilm formation as higher concentrations of iron accumulate in the exopolysaccharide (EPS). Switching from TonB-dependent iron uptake systems to TonB-independent systems not only prevents cells from absorbing excess iron but also conserves energy. Our data suggest that iron uptake strategies are directly regulated by QS in to support their survival in available ecological niches. As iron is an important trace metal for most organisms, its absorption is highly regulated. Fur has been reported as a prevalent regulator of iron acquisition. In addition, there is a relationship between QS and iron acquisition in pathogenic microbes. However, there have been few studies on the iron uptake strategies of nonpathogenic bacteria. In this study, we demonstrated that iron uptake systems in PD1222 were regulated by a newly identified PdeR/PdeI QS system during biofilm formation, and we put forward a hypothesis that QS-dependent iron uptake systems benefit the stability of biofilms. This report elaborates the correlation among QS, iron uptake, and biofilm formation and thus contributes to an understanding of the ecological behavior of environmental bacteria.
是一种有价值的模式生物，因为它具有多功能的呼吸能力和生物能量灵活性，这两者对于其在不同环境中的生存都至关重要。群体感应（QS）在调节许多细胞功能中起着关键作用；然而，QS 系统是否在 中发挥作用尚不清楚。在这项研究中，我们证明了铁摄取系统在 中直接受到新鉴定的 QS 系统的调节。编码 TonB 依赖性系统的基因，该系统运输螯合铁，在 QS 缺陷突变体中转录水平更高。相比之下，编码 Fbp 系统的基因，该系统是 TonB 非依赖性的，并且运输未螯合的三价铁，在突变体中下调。简而言之，QS 在 中触发了生物膜形成过程中铁摄取从 TonB 依赖性到 TonB 非依赖性的转换，因为在胞外多糖（EPS）中积累了更高浓度的铁。从 TonB 依赖性铁摄取系统切换到 TonB 非依赖性系统不仅防止细胞吸收过量的铁，而且还节省能量。我们的数据表明，QS 在 中直接调节铁摄取策略，以支持其在可用生态位中的生存。由于铁是大多数生物体的重要痕量金属，因此其吸收受到高度调节。已经报道 Fur 是铁获取的普遍调节剂。此外，QS 和铁获取在病原微生物中存在关系。然而，关于非病原细菌的铁摄取策略的研究很少。在这项研究中，我们证明了在生物膜形成过程中，PD1222 中的铁摄取系统受到新鉴定的 PdeR/PdeI QS 系统的调节，我们提出了一个假设，即 QS 依赖性铁摄取系统有利于生物膜的稳定性。本报告阐述了 QS、铁摄取和生物膜形成之间的相关性，从而有助于理解环境细菌的生态行为。
