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Xie Q, Wei B, Zhan Z, He Q, Wu K, Chen Y, Liu S, He C, Niu X, Li C, Tang C, Tao J. Arabidopsis membrane protein AMAR1 interaction with type III effector XopAM triggers a hypersensitive response. PLANT PHYSIOLOGY 2023; 193:2768-2787. [PMID: 37648267 DOI: 10.1093/plphys/kiad478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/07/2023] [Accepted: 07/27/2023] [Indexed: 09/01/2023]
Abstract
The efficient infection of plants by the bacteria Xanthomonas campestris pv. campestris (Xcc) depends on its type III effectors (T3Es). Although the functions of AvrE family T3Es have been reported in some bacteria, the member XopAM in Xcc has not been studied. As XopAM has low sequence similarity to reported AvrE-T3Es and different reports have shown that these T3Es have different targets in hosts, we investigated the functions of XopAM in the Xcc-plant interaction. Deletion of xopAM from Xcc reduced its virulence in cruciferous crops but increased virulence in Arabidopsis (Arabidopsis thaliana) Col-0, indicating that XopAM may perform opposite functions depending on the host species. We further found that XopAM is a lipase that may target the cytomembrane and that this activity might be enhanced by its membrane-targeted protein XOPAM-ACTIVATED RESISTANCE 1 (AMAR1) in Arabidopsis Col-0. The binding of XopAM to AMAR1 induced an intense hypersensitive response that restricted Xcc proliferation. Our results showed that the roles of XopAM in Xcc infection are not the same as those of other AvrE-T3Es, indicating that the functions of this type of T3E have differentiated during long-term bacterium‒host interactions.
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Affiliation(s)
- Qingbiao Xie
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
| | - Bingzheng Wei
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
| | - Zhaohong Zhan
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
| | - Qiguang He
- Rubber Research Institute, Chinese Academy of Tropical Agricultural Science, Haikou 571101, China
| | - Kejian Wu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
| | - Yu Chen
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
| | - Shiyao Liu
- Sanya Nanfan Research Institute, Hainan University, Sanya 572024, China
| | - Chaozu He
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
- Sanya Nanfan Research Institute, Hainan University, Sanya 572024, China
- Hainan Yazhou Bay Seed Laboratory, Sanya 572025, China
| | - Xiaolei Niu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
- Sanya Nanfan Research Institute, Hainan University, Sanya 572024, China
| | - Chunxia Li
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
- Hainan Yazhou Bay Seed Laboratory, Sanya 572025, China
| | - Chaorong Tang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
| | - Jun Tao
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
- Hainan Yazhou Bay Seed Laboratory, Sanya 572025, China
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Dual Regulatory Role Exerted by Cyclic Dimeric GMP To Control FsnR-Mediated Bacterial Swimming. mBio 2022; 13:e0141422. [PMID: 36069448 DOI: 10.1128/mbio.01414-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial motility has great medical and ecological significance because of its essential role in bacterial survival and pathogenesis. Cyclic dimeric GMP (c-di-GMP), a second messenger in bacteria, is the predominant regulator of flagellar synthesis and motility and possesses turnover mechanisms that have been thoroughly investigated. Therefore, much attention has been focused on identifying the upstream stimulatory signals and downstream modules that respond to altered c-di-GMP levels. Here, we systematically analyzed c-di-GMP cyclases and phosphodiesterases in Stenotrophomonas maltophilia to screen for motility regulators. Of these enzymes, we identified and characterized a new phosphodiesterase named SisP, which was found to facilitate bacterial swimming upon stimulation with ferrous iron. SisP-mediated degradation of c-di-GMP leads to FsnR-dependent transcription of flagellar genes. Remarkably, c-di-GMP controls FsnR via two independent mechanisms: by direct binding and indirectly by modulating its phosphorylation state. In this study, we deciphered a novel "one stone, two birds" regulatory strategy of c-di-GMP and uncovered the signal that stimulates c-di-GMP hydrolysis. Facilitation of bacterial swimming motility by ferrous iron might contribute to the higher risk of bacterial infection in acutely ill patients. IMPORTANCE Stenotrophomonas maltophilia has become a great threat to human health because of the high mortality of infected patients. Swimming motility plays a crucial role in regulating bacterial virulence and adaptation. However, limited progress has been made in cyclic dimeric GMP (c-di-GMP) controlling swimming motility of S. maltophilia. Here, we characterized c-di-GMP turnover enzymes encoded by S. maltophilia and dissected the regulatory details of a phosphodiesterase named SisP. We demonstrated that SisP degrades c-di-GMP to fully activate FsnR through directly releasing FsnR from the FsnR-c-di-GMP complex and indirectly increasing its phosphorylation level. This finding uncovered a quantitative, rather than an on-off, regulatory manner employed by c-di-GMP to regulate activities of its effectors. Identification of the specific activation of SisP by ferrous iron proposes SisP as a putative drug-target for controlling bacterial infection and ferrous iron at the wounds or cuts as a putative factor contributing to the higher risk of bacterial infection.
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Cai L, Ma W, Zou L, Xu X, Xu Z, Deng C, Qian W, Chen X, Chen G. Xanthomonas oryzae Pv. oryzicola Response Regulator VemR Is Co-opted by the Sensor Kinase CheA for Phosphorylation of Multiple Pathogenicity-Related Targets. Front Microbiol 2022; 13:928551. [PMID: 35756024 PMCID: PMC9218911 DOI: 10.3389/fmicb.2022.928551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
Two-component systems (TCSs) (cognate sensor histidine kinase/response regulator pair, HK/RR) play a crucial role in bacterial adaptation, survival, and productive colonization. An atypical orphan single-domain RR VemR was characterized by the non-vascular pathogen Xanthomonas oryzae pv. oryzicola (Xoc) is known to cause bacterial leaf streak (BLS) disease in rice. Xoc growth and pathogenicity in rice, motility, biosynthesis of extracellular polysaccharide (EPS), and the ability to trigger HR in non-host tobacco were severely compromised in the deletion mutant strain RΔvemR as compared to the wild-type strain RS105. Site-directed mutagenesis and phosphotransfer experiments revealed that the conserved aspartate (D56) residue within the stand-alone phosphoacceptor receiver (REC) domain is essential for phosphorelay and the regulatory activity of Xoc VemR. Yeast two-hybrid (Y2H) and co-immunoprecipitation (co-IP) data identified CheA as the HK co-opting the RR VemR for phosphorylation. Affinity proteomics identified several downstream VemR-interacting proteins, such as 2-oxoglutarate dehydrogenase (OGDH), DNA-binding RR SirA, flagellar basal body P-ring formation protein FlgA, Type 4a pilus retraction ATPase PilT, stress-inducible sensor HK BaeS, septum site-determining protein MinD, cytoskeletal protein CcmA, and Type III and VI secretion system proteins HrpG and Hcp, respectively. Y2H and deletion mutant analyses corroborated that VemR interacted with OGDH, SirA, FlgA, and HrpG; thus, implicating multi-layered control of diverse cellular processes including carbon metabolism, motility, and pathogenicity in the rice. Physical interaction between VemR and HrpG suggested cross-talk interaction between CheA/VemR- and HpaS/HrpG-mediated signal transduction events orchestrating the hrp gene expression.
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Affiliation(s)
- Lulu Cai
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Wenxiu Ma
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Lifang Zou
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiameng Xu
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Zhengyin Xu
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Chaoying Deng
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiaobin Chen
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Gongyou Chen
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
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Lin M, Wu K, Zhan Z, Mi D, Xia Y, Niu X, Feng S, Chen Y, He C, Tao J, Li C. The RavA/VemR two-component system plays vital regulatory roles in the motility and virulence of Xanthomonas campestris. MOLECULAR PLANT PATHOLOGY 2022; 23:355-369. [PMID: 34837306 PMCID: PMC8828458 DOI: 10.1111/mpp.13164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 05/08/2023]
Abstract
Xanthomonas campestris pv. campestris (Xcc) can cause black rot in cruciferous plants worldwide. Two-component systems (TCSs) are key for bacterial adaptation to various environments, including hosts. VemR is a TCS response regulator and crucial for Xcc motility and virulence. Here, we report that RavA is the cognate histidine kinase (HK) of VemR and elucidate the signalling pathway by which VemR regulates Xcc motility and virulence. Genetic analysis showed that VemR is epistatic to RavA. Using bacterial two-hybrid experiments and pull-down and phosphorylation assays, we found that RavA can interact with and phosphorylate VemR, suggesting that RavA is the cognate HK of VemR. In addition, we found that RpoN2 and FleQ are epistatic to VemR in regulating bacterial motility and virulence. In vivo and in vitro experiments demonstrated that VemR interacts with FleQ but not with RpoN2. RavA/VemR regulates the expression of the flagellin-encoding gene fliC by activating the transcription of the rpoN2-vemR-fleQ and flhF-fleN-fliA operons. In summary, our data show that the RavA/VemR TCS regulates FleQ activity and thus influences the expression of motility-related genes, thereby affecting Xcc motility and virulence. The identification of this novel signalling pathway will deepen our understanding of Xcc-plant interactions.
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Affiliation(s)
- Maojuan Lin
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Kejian Wu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Zhaohong Zhan
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Duo Mi
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Yingying Xia
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Xiaolei Niu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Shipeng Feng
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Yinhua Chen
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Chaozu He
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Jun Tao
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Chunxia Li
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
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Wei C, Wang S, Liu P, Cheng ST, Qian G, Wang S, Fu Y, Qian W, Sun W. The PdeK-PdeR two-component system promotes unipolar localization of FimX and pilus extension in Xanthomonas oryzae pv. oryzicola. Sci Signal 2021; 14:eabi9589. [PMID: 34520229 DOI: 10.1126/scisignal.abi9589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
[Figure: see text].
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Affiliation(s)
- Chao Wei
- Department of Plant Pathology and MOA Key Laboratory of Pest Monitoring and Green Management, and Joint International Research Laboratory of Crop Molecular Breeding, Ministry of Education, China Agricultural University, Beijing 100193, China
| | - Shanzhi Wang
- Department of Plant Pathology and MOA Key Laboratory of Pest Monitoring and Green Management, and Joint International Research Laboratory of Crop Molecular Breeding, Ministry of Education, China Agricultural University, Beijing 100193, China
| | - Pengwei Liu
- College of Plant Protection, Jilin Agricultural University, Changchun 130118, Jilin, China
| | - Shou-Ting Cheng
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Guoliang Qian
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Shuwei Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenxian Sun
- Department of Plant Pathology and MOA Key Laboratory of Pest Monitoring and Green Management, and Joint International Research Laboratory of Crop Molecular Breeding, Ministry of Education, China Agricultural University, Beijing 100193, China.,College of Plant Protection, Jilin Agricultural University, Changchun 130118, Jilin, China
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The clpX gene plays an important role in bacterial attachment, stress tolerance, and virulence in Xanthomonas campestris pv. campestris. Arch Microbiol 2019; 202:597-607. [PMID: 31741013 DOI: 10.1007/s00203-019-01772-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 10/20/2019] [Accepted: 11/07/2019] [Indexed: 01/24/2023]
Abstract
Xanthomonas campestris pv. campestris is a bacterial pathogen and the causal agent of black rot in crucifers. In this study, a clpX mutant was obtained by EZ-Tn5 transposon mutagenesis of the X. campestris pv. campestris. The clpX gene was annotated to encode ClpX, the ATP-binding subunit of ATP-dependent Clp protease. The clpX mutant exhibited reduced bacterial attachment, extracellular enzyme production and virulence. Mutation of clpX also resulted in increased sensitivity to a myriad of stresses, including heat, puromycin, and sodium dodecyl sulfate. These altered phenotypes of the clpX mutant could be restored to wild-type levels by in trans expression of the intact clpX gene. Proteomic analysis revealed that the expression of 211 proteins differed not less than twofold between the wild-type and mutant strains. Cluster of orthologous group analysis revealed that these proteins are mainly involved in metabolism, cell wall biogenesis, chaperone, and signal transduction. The reverse transcription quantitative real-time polymerase chain reaction analysis demonstrated that the expression of genes encoding attachment-related proteins, extracellular enzymes, and virulence-associated proteins was reduced after clpX mutation. The results in this study contribute to the functional understanding of the role of clpX in Xanthomonas for the first time, and extend new insights into the function of clpX in bacteria.
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Cheng ST, Wang FF, Qian W. Cyclic-di-GMP binds to histidine kinase RavS to control RavS-RavR phosphotransfer and regulates the bacterial lifestyle transition between virulence and swimming. PLoS Pathog 2019; 15:e1007952. [PMID: 31408509 PMCID: PMC6707612 DOI: 10.1371/journal.ppat.1007952] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 08/23/2019] [Accepted: 06/30/2019] [Indexed: 12/28/2022] Open
Abstract
The two-component signalling system (TCS) comprising a histidine kinase (HK) and a response regulator (RR) is the predominant bacterial sense-and-response machinery. Because bacterial cells usually encode a number of TCSs to adapt to various ecological niches, the specificity of a TCS is in the centre of regulation. Specificity of TCS is defined by the capability and velocity of phosphoryl transfer between a cognate HK and a RR. Here, we provide genetic, enzymology and structural data demonstrating that the second messenger cyclic-di-GMP physically and specifically binds to RavS, a HK of the phytopathogenic, gram-negative bacterium Xanthomonas campestris pv. campestris. The [c-di-GMP]-RavS interaction substantially promotes specificity between RavS and RavR, a GGDEF–EAL domain-containing RR, by reinforcing the kinetic preference of RavS to phosphorylate RavR. [c-di-GMP]-RavS binding effectively decreases the phosphorylation level of RavS and negatively regulates bacterial swimming. Intriguingly, the EAL domain of RavR counteracts the above regulation by degrading c-di-GMP and then increasing the level of phosphorylated RavS. Therefore, RavR acts as a bifunctional phosphate sink that finely controls the level of phosphorylated RavS. These biochemical processes interactively modulate the phosphoryl flux between RavS-RavR and bacterial lifestyle transition. Our results revealed that c-di-GMP acts as an allosteric effector to dynamically modulate specificity between HK and RR. c-di-GMP is a multifunctional bacterial second messenger that controls various physiological processes. The nucleotide derivative binds to riboswitches or proteins as effectors during regulation. Here, we found that c-di-GMP physically binds to a histidine kinase, RavS, of a plant pathogenic bacterium. The binding event significantly enhanced the phosphotransferase activity of RavS to phosphorylate a response regulator, RavR. This process tightly modulates the phosphorylation level of RavS, which is important to the lifestyle transition of the bacterium between virulence and swimming motility. Therefore, our results reveal that c-di-GMP controls the bacterial two-component signalling, one of the dominant mechanisms of bacterial cells in adaptation to various environmental stimuli.
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Affiliation(s)
- Shou-Ting Cheng
- State Key Laboratory of Plant Genomics, Institution of Microbiology, Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Plant Genomics, Institution of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, China
| | - Fang-Fang Wang
- State Key Laboratory of Plant Genomics, Institution of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institution of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- Center for Excellence in Biotic Interactions, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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A Two-Component System That Modulates Cyclic di-GMP Metabolism Promotes Legionella pneumophila Differentiation and Viability in Low-Nutrient Conditions. J Bacteriol 2019; 201:JB.00253-19. [PMID: 31209078 DOI: 10.1128/jb.00253-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/12/2019] [Indexed: 01/06/2023] Open
Abstract
During its life cycle, the environmental pathogen Legionella pneumophila alternates between a replicative and transmissive cell type when cultured in broth, macrophages, or amoebae. Within a protozoan host, L. pneumophila further differentiates into the hardy cell type known as the mature infectious form (MIF). The second messenger cyclic di-GMP coordinates lifestyle changes in many bacterial species, but its role in the L. pneumophila life cycle is less understood. Using an in vitro broth culture model that approximates the intracellular transition from the replicative to the transmissive form, here we investigate the contribution to L. pneumophila differentiation of a two-component system (TCS) that regulates cyclic di-GMP metabolism. The TCS is encoded by lpg0278-lpg0277 and is cotranscribed with lpg0279, which encodes a protein upregulated in MIF cells. The promoter for this operon is RpoS dependent and induced in nutrient-limiting conditions that do not support replication, as demonstrated using a gfp reporter and quantitative PCR (qPCR). The response regulator of the TCS (Lpg0277) is a bifunctional enzyme that both synthesizes and degrades cyclic di-GMP. Using a panel of site-directed point mutants, we show that cyclic di-GMP synthesis mediated by a conserved GGDEF domain promotes growth arrest of replicative L. pneumophila, accumulation of pigment and poly-3-hydroxybutyrate storage granules, and viability in nutrient-limiting conditions. Genetic epistasis tests predict that the MIF protein Lpg0279 acts as a negative regulator of the TCS. Thus, L. pneumophila is equipped with a regulatory network in which cyclic di-GMP stimulates the switch from a replicative to a resilient state equipped to survive in low-nutrient environments.IMPORTANCE Although an intracellular pathogen, L. pneumophila has developed mechanisms to ensure long-term survival in low-nutrient aqueous conditions. Eradication of L. pneumophila from contaminated water supplies has proven challenging, as outbreaks have been traced to previously remediated systems. Understanding the genetic determinants that support L. pneumophila persistence in low-nutrient environments can inform design and assessment of remediation strategies. Here we characterize a genetic locus that encodes a two-component signaling system (lpg0278-lpg0277) and a putative regulator protein (lpg0279) that modulates the production of the messenger molecule cyclic di-GMP. We show that this locus promotes both L. pneumophila cell differentiation and survival in nutrient-limiting conditions, thus advancing the understanding of the mechanisms that contribute to L. pneumophila environmental resilience.
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Hu Q, Zhang J, Chen Y, Hu L, Li W, He ZG. Cyclic di-GMP co-activates the two-component transcriptional regulator DevR in Mycobacterium smegmatis in response to oxidative stress. J Biol Chem 2019; 294:12729-12742. [PMID: 31270210 DOI: 10.1074/jbc.ra119.008252] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/20/2019] [Indexed: 12/27/2022] Open
Abstract
Cyclic di-GMP (c-di-GMP) is an important second messenger in bacteria, and its regulatory network has been extensively studied. However, information regarding the activation mechanisms of its receptors remains limited. In this study, we characterized the two-component regulator DevR as a new c-di-GMP receptor and further uncovered a novel co-activation mechanism for effective regulation of DevR in mycobacteria. We show that high c-di-GMP levels induce the expression of the devR operon in Mycobacterium smegmatis and increase mycobacterial survival under oxidative stress. The deletion of either DevR or its two-component kinase DevS significantly weakened the stimulating effect of c-di-GMP on oxidative-stress tolerance of mycobacteria. We also found that DevR senses the c-di-GMP signal through its C-terminal structure and that c-di-GMP alone does not directly affect the DNA-binding activity of DevR. Strikingly, c-di-GMP stimulated DevR phosphorylation by the kinase DevS, thereby activating DevR's DNA-binding affinity. In summary, our results indicated that c-di-GMP triggers a phosphorylation-dependent mechanism that co-activates DevR's transcriptional activity. Our findings suggest a novel paradigm for the cross-talk between c-di-GMP signaling and two-component regulatory systems that activates transcription of stress-response genes in bacteria.
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Affiliation(s)
- Qingbin Hu
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jiaxun Zhang
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yu Chen
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lihua Hu
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Weihui Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Zheng-Guo He
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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Liao CT, Chiang YC, Hsiao YM. Functional characterization and proteomic analysis of lolA in Xanthomonas campestris pv. campestris. BMC Microbiol 2019; 19:20. [PMID: 30665348 PMCID: PMC6341742 DOI: 10.1186/s12866-019-1387-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 01/02/2019] [Indexed: 12/31/2022] Open
Abstract
Background The gram-negative Xanthomonas campestris pv. campestris is the pathogenic bacterium that causes black rot disease in crucifers. The virulence determinants of this bacterium include extracellular enzymes, exopolysaccharides, and biofilm formation. Here, one transposon mutant of X. campestris pv. campestris strain 17 that affects biofilm formation was isolated, and subsequent analyses led to the identification of the lolA gene, which encodes an outer membrane lipoprotein chaperone. Results The lolA mutant exhibited significant reductions in bacterial attachment, extracellular enzyme production, virulence, and tolerance in the presence of myriad membrane-perturbing agents. These phenotypic changes of the mutant could be complemented to the wild-type level through the intact lolA gene. Proteomic analysis revealed that 109 proteins were differentially expressed after lolA mutation. These differentially expressed proteins were categorized in various functional groups and were mainly associated with the membrane component, were involved in transport, and contained receptor activity. Through reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) analysis, deletion of lolA was determined to have caused significantly reduced expression of genes that encode the major extracellular enzymes, the biofilm-related proteins, and the virulence-related proteins. The RT-qPCR analysis also indicated that the expression of several genes that encode putative outer membrane lipoproteins and TonB-dependent receptors was reduced after lolA mutation. Conclusions This is the first report to define the lolA gene as a virulence factor and to contribute to the functional understanding of, and provide new information concerning, the role of lolA in Xanthomonas. Furthermore, the results of this study provide and extend new insights into the function of lolA in bacteria. Electronic supplementary material The online version of this article (10.1186/s12866-019-1387-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Ying-Chuan Chiang
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan.
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Zhang ZC, Zhao M, Xu LD, Niu XN, Qin HP, Li YM, Li ML, Jiang ZW, Yang X, Huang GH, Jiang W, Tang JL, He YQ. Genome-Wide Screening for Novel Candidate Virulence Related Response Regulator Genes in Xanthomonas oryzae pv. oryzicola. Front Microbiol 2018; 9:1789. [PMID: 30131784 PMCID: PMC6090019 DOI: 10.3389/fmicb.2018.01789] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 07/17/2018] [Indexed: 11/13/2022] Open
Abstract
Two-component regulatory system (TCS), a major type of cellular signal transduction system, is widely used by bacteria to adapt to different conditions and to colonize certain ecological niches in response to environmental stimuli. TCSs are of distinct functional diversity, genetic diversity, and species specificity (pathovar specificity, even strain specificity) across bacterial groups. Although TCSs have been demonstrated to be crucial to the virulence of Xanthomonas, only a few researches have been reported about the studies of TCSs in Xanthomonas oryzae pathovar oryzicola (hereafter Xoc), the pathogen of rice bacterial streak disease. In the genome of Xoc strain GX01, it has been annotated 110 TCSs genes encoding 54 response regulators (RRs), 36 orthodox histidine kinase (HKs) and 20 hybrid histidine kinase (HyHKs). To evaluate the involvement of TCSs in the stress adaptation and virulence of Xoc, we mutated 50 annotated RR genes in Xoc GX01 by homologous vector integration mutagenesis and assessed their phenotypes in given conditions and tested their virulence on host rice. 17 RR genes were identified to be likely involved in virulence of Xoc, of which 10 RR genes are novel virulence genes in Xanthomonas, including three novel virulence genes for bacteria. Of the novel candidate virulence genes, some of which may be involved in the general stress adaptation, exopolysaccharide production, extracellular protease secretion and swarming motility of Xoc. Our results will facilitate further studies on revealing the biological functions of TCS genes in this phytopathogenic bacterium.
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Affiliation(s)
- Zheng-Chun Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China.,College of Agronomy, Guangxi University, Nanning, China
| | - Min Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Li-Dan Xu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Xiang-Na Niu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Hong-Ping Qin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Yi-Ming Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Mei-Lin Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Zhong-Wei Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Xia Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Guang-Hui Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Wei Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Yong-Qiang He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
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12
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Wang H, Shi C, Xie Q, Wang Y, Liu S, Li C, He C, Tao J. Genome-Wide Analysis of β-Galactosidases in Xanthomonas campestris pv. campestris 8004. Front Microbiol 2018; 9:957. [PMID: 29867862 PMCID: PMC5958218 DOI: 10.3389/fmicb.2018.00957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 04/24/2018] [Indexed: 11/29/2022] Open
Abstract
Bacterial β-galactosidase is involved in lactose metabolism and acts as a prevalent reporter enzyme used in studying the activities of prokaryotic and eukaryotic promoters. Xanthomonas campestris pv. campestris (Xcc) is the pathogen of black rot disease in crucifers. β-Galactosidase activity can be detected in Xcc culture, which makes Escherichia coli LacZ unable to be used as a reporter enzyme in Xcc. To systemically understand the β-galactosidase in Xcc and construct a β-galactosidase -deficient strain for promoter activity analysis using LacZ as a reporter, we here analyzed the putative β-galactosidases in Xcc 8004. As glycosyl hydrolase (GH) family 2 (GH2) and 35 (GH35) family enzymes were reported to have beta-galactosidase activities, we studied all of them encoded by Xcc 8004. When expressed in E. coli, only two of the enzymes, XC1214 and XC2985, were found to have β-galactosidase activity. When deleted from the Xcc 8004 genome, only the XC1214 mutant had no β-galactosidase activity, and other GH2 and GH35 gene deletions resulted in no significant reduction in β-galactosidase activity. Therefore, XC1214 is the main β-galactosidase in Xcc 8004. Notably, we have constructed a β-galactosidase-free strain that can be employed in gene traps using LacZ as a reporter in Xcc. The results reported herein should facilitate the development of high-capacity screening assays that utilize the LacZ reporter system in Xcc.
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Affiliation(s)
- Huiqi Wang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Haikou, China.,Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Chenyi Shi
- Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Qingbiao Xie
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Haikou, China.,Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Yaxin Wang
- Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Shiyao Liu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Haikou, China.,Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Chunxia Li
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Haikou, China.,Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Chaozu He
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Haikou, China.,Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Jun Tao
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Haikou, China.,Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
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13
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Liu YF, Liao CT, Chiang YC, Li CE, Hsiao YM. WxcX is involved in bacterial attachment and virulence in Xanthomonas campestris pv. campestris. J Basic Microbiol 2018; 58:403-413. [PMID: 29504631 DOI: 10.1002/jobm.201700591] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 02/06/2018] [Accepted: 02/07/2018] [Indexed: 11/08/2022]
Abstract
Xanthomonas campestris pv. campestris (Xcc) is the causative agent of black rot in crucifers. Here, one EZ-Tn5 transposon mutant of Xcc, altered in bacterial attachment, was isolated. Further analysis revealed that the transposon was inserted in the wxcX gene (encodes a hypothetical protein) of the transposon mutant. Sequence analysis revealed that WxcX is highly conserved in Xanthomonas, but none has been characterized. In this study, it was indicated that mutation of wxcX resulted in enhanced bacterial attachment, reduced virulence on the host cabbage, and increased sensitivity to sodium dodecyl sulfate. The affected phenotypes of the wxcX mutant could be complemented to wild-type levels by the intact wxcX gene. Site-directed mutagenesis revealed that E408 and E411 are critical amino acid residues for WxcX function in bacterial attachment. Taken together, our results demonstrate the roles of wxcX in attachment, virulence, and tolerance to sodium dodecyl sulfate in Xanthomonas for the first time.
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Affiliation(s)
- Yu-Fan Liu
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan.,Division of Allergy, Department of Pediatrics, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Ying-Chuan Chiang
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Chih-En Li
- Graduate Institute of Biotechnology and Biomedical Engineering, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
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14
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Su J, Zou X, Huang L, Bai T, Liu S, Yuan M, Chou SH, He YW, Wang H, He J. DgcA, a diguanylate cyclase from Xanthomonas oryzae pv. oryzae regulates bacterial pathogenicity on rice. Sci Rep 2016; 6:25978. [PMID: 27193392 PMCID: PMC4872155 DOI: 10.1038/srep25978] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 04/26/2016] [Indexed: 12/28/2022] Open
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice blight disease as well as a serious phytopathogen worldwide. It is also one of the model organisms for studying bacteria-plant interactions. Current progress in bacterial signal transduction pathways has identified cyclic di-GMP as a major second messenger molecule in controlling Xanthomonas pathogenicity. However, it still remains largely unclear how c-di-GMP regulates the secretion of bacterial virulence factors in Xoo. In this study, we focused on the important roles played by DgcA (XOO3988), one of our previously identified diguanylate cyclases in Xoo, through further investigating the phenotypes of several dgcA-related mutants, namely, the dgcA-knockout mutant ΔdgcA, the dgcA overexpression strain OdgcA, the dgcA complemented strain CdgcA and the wild-type strain. The results showed that dgcA negatively affected virulence, EPS production, bacterial autoaggregation and motility, but positively triggered biofilm formation via modulating the intracellular c-di-GMP levels. RNA-seq data further identified 349 differentially expressed genes controlled by DgcA, providing a foundation for a more solid understanding of the signal transduction pathways in Xoo. Collectively, the present study highlights DgcA as a major regulator of Xoo virulence, and can serve as a potential target for preventing rice blight diseases.
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Affiliation(s)
- Jianmei Su
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xia Zou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Liangbo Huang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Tenglong Bai
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Shu Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Meng Yuan
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Shan-Ho Chou
- Institute of Biochemistry, and NCHU Agricultural Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan
| | - Ya-Wen He
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Haihong Wang
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510650, China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
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15
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Liao CT, Liu YF, Chiang YC, Lo HH, Du SC, Hsu PC, Hsiao YM. Functional characterization and transcriptome analysis reveal multiple roles for prc in the pathogenicity of the black rot pathogen Xanthomonas campestris pv. campestris. Res Microbiol 2016; 167:299-312. [PMID: 26804425 DOI: 10.1016/j.resmic.2016.01.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 12/29/2015] [Accepted: 01/06/2016] [Indexed: 10/22/2022]
Abstract
Gram-negative phytopathogenic Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot in crucifers. The ability of Xcc to incite this disease in plants depends on a number of factors, including exopolysaccharides, extracellular enzymes and biofilm production. In this study, transposon mutagenesis led to identification of the prc gene, encoding a tail-specific protease, which plays a role in Xcc pathogenesis. Mutation of prc resulted in decreased virulence, extracellular protease production and bacterial attachment, with restoration to the levels of wild type by the intact prc gene. From subsequent quantitative RT-PCR analysis and reporter assay, the major extracellular protease gene prt1, biofilm-related gene galE encoding a UDP-galactose 4-epimerase and two putative adhesin genes (yapH and XC_4290 encoding autotransporter-like protein H and hemagglutinin, respectively) were found to be reduced in the prc mutant. Results of transcriptome profiling of Xcc wild type and prc mutant by RNA sequencing (RNA-Seq) showed that mutation of prc in Xcc leads to alteration in the transcriptional levels (more than twofold) of 91 genes. These differentially expressed genes were associated with a wide range of biological functions such as carbohydrate transport and metabolism, cell wall/membrane biogenesis, posttranslational modification, protein turnover and chaperones, inorganic ion transport and metabolism and signal transduction mechanisms. The results of this study facilitate the functional understanding of and provide new information about the regulatory role of prc.
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Affiliation(s)
- Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Yu-Fan Liu
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung 402, Taiwan.
| | - Ying-Chuan Chiang
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Hsueh-Hsia Lo
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Shin-Chiao Du
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Pei-Chi Hsu
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
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16
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Genome-wide identification of genes necessary for biofilm formation by nosocomial pathogen Stenotrophomonas maltophilia reveals that orphan response regulator FsnR is a critical modulator. Appl Environ Microbiol 2016; 81:1200-9. [PMID: 25480754 DOI: 10.1128/aem.03408-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Stenotrophomonas maltophilia is a Gram-negative bacterial pathogen of increasing concern to human health. Most clinical isolates of S. maltophilia efficiently form biofilms on biotic and abiotic surfaces, making this bacterium resistant to a number of antibiotic treatments and therefore difficult to eliminate. To date, very few studies have investigated the molecular and regulatory mechanisms responsible for S. maltophilia biofilm formation. Here we constructed a random transposon insertion mutant library of S. maltophilia ATCC 13637 and screened 14,028 clones. A total of 46 nonredundant genes were identified. Mutants of these genes exhibited marked changes in biofilm formation, suggesting that multiple physiological pathways, including extracellular polysaccharide production, purine synthesis, transportation, and peptide and lipid synthesis, are involved in bacterial cell aggregation. Of these genes, 20 putatively contributed to flagellar biosynthesis, indicating a critical role for cell motility in S.maltophilia biofilm formation. Genetic and biochemical evidence demonstrated that an orphan response regulator, FsnR, activated transcription of at least two flagellum-associated operons by directly binding to their promoters. This regulatory protein plays a fundamental role in controlling flagellar assembly, cell motility, and biofilm formation. These results provide a genetic basis to systematically study biofilm formation of S. maltophilia.
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