Cyclic di-GMP Is Integrated Into a Hierarchal Quorum Sensing Network Regulating Antimicrobial Production and Biofilm Formation in Roseobacter Clade Member Rhodobacterales Strain Y4I
Cyclic di-GMP Is Integrated Into a Hierarchal Quorum Sensing Network Regulating Antimicrobial Production and Biofilm Formation in Roseobacter Clade Member Rhodobacterales Strain Y4I
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DOI：
10.3389/fmars.2021.681551
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发表时间：
2021-07-05
影响因子：
3.7
通讯作者：
Buchan, Alison
中科院分区：
文献类型：
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作者：
Armes, April C.;Buchan, Alison
与海洋颗粒有机物相关的微生物生物膜进行影响局部和区域生物地球化学循环的转化。早期的微生物定居者通常被假设为通过N-酰基高丝氨酸内酯（阿勒）介导的群体感应（QS）为生物膜结构，动力学和功能“设置阶段”。AHL以及抗菌剂的产生有助于蔷薇属进化枝成员的定殖成功。这组丰富的海洋细菌的一个成员，Rhododocalales sp.Y4I，具有两个QS系统，phaRI（QS 1）和pgaRI（QS 2）。在这里，我们在两个QS系统的突变体的特点提供遗传证据，这两个系统的工作在分层的方式，以协调生产的抗菌靛蓝以及生物膜的形成。pgaR（QS 2）中的突变导致编码QS系统以及控制靛蓝的生物合成的基因的表达降低。相比之下，QS 1的突变并没有显著影响QS 2的基因表达。向QS 1和QS 2突变体中添加外源AHLs导致QS 1而非QS 2的靛蓝生产的部分恢复（WT的45-60%）。突变中断的QS 1有一个更明显的效果比那些在QS 2的生物膜的发展。最后，我们证明，c-di-GMP水平改变QS和靛红合成Y 4 I突变体。总之，这些结果表明，pgaRI（QS 2）是在一个管理靛蓝生物合成的监管层次的顶部，全球监管代谢产物，c-di-GMP，可能整合到该菌株的QS电路。这些发现提供了对生理过程的机械理解，这些生理过程对于阐明自然界中驱动玫瑰杆菌竞争力的因素非常重要。
Microbial biofilms associated with marine particulate organic matter carry out transformations that influence local and regional biogeochemical cycles. Early microbial colonizers are often hypothesized to "set the stage" for biofilm structure, dynamics, and function via N-acyl homoserine lactone (AHL)-mediated quorum sensing (QS). Production of AHLs, as well as antimicrobials, contributes to the colonization success of members of the Roseobacter clade. One member of this group of abundant marine bacteria, Rhodobacterales sp. Y4I, possesses two QS systems, phaRI (QS1) and pgaRI (QS2). Here, we characterize mutants in both QS systems to provide genetic evidence that the two systems work in hierarchical fashion to coordinate production of the antimicrobial indigoidine as well as biofilm formation. A mutation in pgaR (QS2) results in decreased expression of genes encoding both QS systems as well as those governing the biosynthesis of indigoidine. In contrast, mutations in QS1 did not significantly influence gene expression of QS2. Addition of exogenous AHLs to QS1 and QS2 mutants led to partial restoration of indigoidine production (45-60% of WT) for QS1 but not QS2. Mutational disruptions of QS1 had a more pronounced effect on biofilm development than those in QS2. Finally, we demonstrate that c-di-GMP levels are altered in QS and indigoidine biosynthesis Y4I mutants. Together, these results indicate that pgaRI (QS2) is at the top of a regulatory hierarchy governing indigoidine biosynthesis and that the global regulatory metabolite, c-di-GMP, is likely integrated into the QS circuitry of this strain. These findings provide mechanistic understanding of physiological processes that are important in elucidating factors driving competitiveness of Roseobacters in nature.