RasI/R Quorum Sensing System Controls the Virulence of Ralstonia solanacearum Strain EP1
RasI/R Quorum Sensing System Controls the Virulence of Ralstonia solanacearum Strain EP1
复制标题
RasI/R 群体感应系统控制青枯罗尔斯顿菌 EP1 菌株的毒力
DOI：
10.1128/aem.00325-22
复制
发表时间：
2022-07-25
影响因子：
4.4
通讯作者：
Zhang, Lianhui
中科院分区：
文献类型：
--
作者：
Yan, Jinli;Li, Peng;Zhang, Lianhui
群体感应（QS）是一种广泛保守的细菌调节机制，其依赖于产生和感知自诱导化学信号来协调多种合作活动，例如毒力，胞外酶分泌和生物膜形成。青枯雷尔氏菌（Ralsroniasolanacearum）是一种引起植物严重青枯病的病原菌，其PhcBSR QS系统在其生理和毒力调控中起着重要作用。在本研究中，我们发现R.青枯菌菌株EP 1含有编码未表征的LuxI/LuxR（LuxI/R）QS同源物（RasI/RasR [此处指定为RasI/R））的基因。为了确定RasI/R系统在菌株EP 1中的作用，我们构建了一个RasI/R系统催化信号的特异性报告基因，Rash层析分离和结构分析表明RasI主要合成N-（3-羟基十二烷酰基）-高丝氨酸内酯（3-OH-C12-HSL）。此外，我们还发现rasl基因的转录表达受RasR的调控，RasI/R系统在调节纤维素酶的产生、运动性、生物膜形成、氧化应激反应和致病性等方面起着重要作用。青枯菌EP 1.然后，我们通过使用转录组测序（RNA-seq）分析确定RasI/R调节子来进一步表征该系统，这表明该新鉴定的QS系统调节与细菌生理学和致病特性相关的超过154个基因的转录表达。综上所述，本研究的结果提出了一个重要的新的QS系统的调节R。重要意义群体感应（Quorum sensing，QS）是许多植物病原细菌毒力因子的关键调控因子，它是植物病原细菌致病力的重要调控因子。以前的研究揭示了两个QS系统（即，PhcBSR和SolI/R）。青枯菌菌株PhcBSR QS系统在细菌毒力调控中起着关键作用，LuxI/LuxR（SolI/R）QS系统在许多R.青枯菌菌株在这项研究中，一个新的功能QS系统（即，RasI/R）在R.从受感染茄子中分离的青枯菌EP 1菌株。表型分析表明，RasI/R系统在调节一系列与细菌毒力相关的生物活性中起着重要作用。该QS系统产生并响应QS信号3-OH-C12-HSL，从而调节细菌存活和感染的关键能力。迄今为止，R.青枯菌菌株仍然没有被很好地理解。我们的研究结果为复杂的QS调控网络提供了新的见解，这些网络控制着R的生理和毒力。为青枯病的防治提供了有效的靶标和线索。
Quorum sensing (QS) is a widely conserved bacterial regulatory mechanism that relies on production and perception of autoinducing chemical signals to coordinate diverse cooperative activities, such as virulence, exoenzyme secretion, and biofilm formation. In Ralsronia solanacearum, a phytopathogen causing severe bacterial wilt diseases in many plant species, previous studies identified the PhcBSR QS system, which plays a key role in regulation of its physiology and virulence. In this study, we found that R. solanacearum strain EP1 contains the genes encoding uncharacterized LuxI/LuxR (LuxI/R) QS homologues (RasI/RasR [designated RasI/R here)). To determine the roles of the RasI/R system in strain EP1, we constructed a specific reporter for the signals catalyzed by Rash Chromatography separation and structural analysis showed that RasI synthesized primarily N-(3-hydroxydodecanoyl)-homoserine lactone (3-OH-C12-HSL). In addition, we showed that the transcriptional expression of rasl is regulated by RasR in response to 3-OH-C12-HSL Phenotype analysis unveiled that the RasI/R system plays a critical role in modulation of cellulase production, motility, biofilm formation, oxidative stress response, and virulence of R. solanacearum EP1. We then further characterized this system by determining the RasI/R regulon using transcriptome sequencing (RNA-seq) analysis, which showed that this newly identified QS system regulates the transcriptional expression of over 154 genes associated with bacterial physiology and pathogenic properties. Taken together, the findings from this study present an essential new QS system in regulation of R. solanacearum physiology and virulence and provide new insight into the complicated regulatory mechanisms and networks in this important plant pathogen.IMPORTANCE Quorum sensing (QS) is a key regulator of virulence factors in many plant-pathogenic bacteria. Previous studies unveiled two QS systems (i.e., PhcBSR and SolI/R) in several R. solanacearum strains. The PhcBSR QS system is known for its key roles in regulation of bacterial virulence, and the LuxI/LuxR (SolI/R) QS system appears dispensable for pathogenicity in a number of R. solanacearum strains. In this study, a new functional QS system (i.e., RasI/R) was identified and characterized in R. solanacearum strain EP1 isolated from infected eggplants. Phenotype analyses showed that the RasI/R system plays an important role in regulation of a range of biological activities associated with bacterial virulence. This QS system produces and responds to the QS signal 3-OH-C12-HSL and hence regulates critical bacterial abilities in survival and infection. To date, multiple QS signaling circuits in R. solanacearum strains are still not well understood. Our findings from this study provide new insight into the complicated QS regulatory networks that govern the physiology and virulence of R. solanacearum and present a valid target and clues for the control and prevention of bacterial wilt diseases.